Glass-based articles having a hard film and a crack mitigating composite structure for retained article strength and scratch resistance

ABSTRACT

An article that includes: a glass-based substrate comprising opposing major surfaces; a crack mitigating composite over one of the major surfaces, the composite comprising an inorganic element and a polymeric element; and a hard film disposed on the crack mitigating composite comprising an elastic modulus greater than or equal to the elastic modulus of the glass-based substrate. The crack mitigating composite is characterized by an elastic modulus of greater than 30 GPa. Further, the hard film comprises at least one of a metal-containing oxide, a metal-containing oxynitride, a metal-containing nitride, a metal-containing carbide, a silicon-containing polymer, a carbon, a semiconductor, and combinations thereof.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 37 U.S.C. § 371 toInternational Patent Application No. PCT/US2018/023974, filed Mar. 23,2018, which claims the benefit of priority under 35 U.S.C. § 119 to U.S.Provisional Patent Application No. 62/477,708, filed Mar. 28, 2017, thecontents of all of which are relied upon and incorporated herein byreference in their entirety.

BACKGROUND

This disclosure relates to articles with a glass-based substrate thathas a scratch-resistant film disposed on its surface, and display deviceapplications thereof.

Articles including a glass-based substrate, which may be strengthened orstrong as described herein, have found wide usage recently as aprotective cover glass for displays, especially in touch-screenapplications, and there is a potential for their use in many otherapplications, for example automotive or architectural windows, glass forphotovoltaic systems and glass-based substrates for use in otherelectronic device applications. Further, such articles are often used inconsumer electronic products to protect devices within the product, toprovide a user interface for input and/or display, and/or many otherfunctions. These consumer electronic products include mobile devices,for example smart phones, mp3 players and computer tablets.

Strong optical performance is beneficial in many of these articles interms of maximum light transmission and minimum reflectivity when thearticles are used in cover substrate and in some housing substrateapplications. In addition, in cover substrate applications it isdesirable that the color exhibited or perceived, in reflection and/ortransmission, does not change appreciably as the viewing angle (orincident illumination angle) is changed. That is, if the color,reflectivity or transmission changes with viewing angle to anappreciable degree, the user of the product incorporating the coverglass will perceive a change in the color or brightness of the display,which can diminish the perceived quality of the display. Of thesechanges, a change in color is often the most noticeable andobjectionable to users.

In many of these applications it can be advantageous to apply ascratch-resistant film to the glass-based substrates. Suchscratch-resistant films can also include other functional film(s) and/orlayer(s) disposed between an outer scratch-resistant film and thesubstrate. As such, exemplary scratch-resistant films can include one ormore layers or films of the following materials: indium-tin-oxide (ITO)or other transparent conductive oxides (e.g., aluminum and gallium dopedzinc oxides and fluorine doped tin oxide), hard films of various kinds(e.g., diamond-like carbon, Al₂O₃, AlN, AlO_(x)N_(y), Si₃N₄,SiO_(x)N_(y), Si_(u)Al_(x)O_(y)N_(z), TiN, TiC), IR or UV reflectinglayers, conducting or semiconducting layers, electronics layers,thin-film-transistor layers, or anti-reflection (AR) films (e.g., SiO₂,Nb₂O₅ and TiO₂ layered structures). These scratch-resistant films,whether stand-alone or multi-layer, are desired to have a high scratchresistance and are often hard and/or have a high elastic modulus, orotherwise their other functional properties or those of the substratebeneath them (e.g., mechanical, durability, electrical conductivity,and/or optical properties) will be degraded. In most cases thesescratch-resistant films are thin films; consequently, they generallyhave a thickness in the range of 0.005 μm to 10 μm (e.g., 5 nm to 10,000nm).

When a scratch-resistant film is applied to a surface of a glass-basedsubstrate, which may be strengthened or characterized as strong, theaverage flexural strength of the glass-based substrate may be reduced,for example, when evaluated using ring-on-ring strength testing. Thisbehavior has been measured to be independent of temperature effects(i.e., the behavior is not caused by significant or measurablerelaxation of surface compressive stress in the strengthened glass-basedsubstrate due to any heating). The reduction in average flexuralstrength is also apparently independent of any glass surface damage orcorrosion from processing, and is apparently an inherent mechanicalattribute of the article, even when thin, scratch-resistant films havinga thickness in the range from about 5 nm to about 10 μm are applied tothe article. Without being bound by theory, this reduction in averageflexural strength is believed to be associated with the adhesion betweena scratch-resistant film relative to the strengthened or strongglass-based substrates, the initially high average flexural strength (orhigh average strain-to-failure) of selected strengthened or strongglass-based substrates relative to selected, scratch-resistant films,together with crack bridging between such a film and the glass-basedsubstrate.

When these articles employing glass-based substrates are employed incertain electronic device applications, for example, they may besubjected to additional high temperature processing duringmanufacturing. More specifically, the articles can be subjected toadditional thermal treatments after deposition of the scratch-resistantfilm on the glass-based substrates. These additional high temperaturetreatments often are the result of application-specific development ofadditional structures and components on the substrates and/or films ofthe article. Further, the deposition of the scratch-resistant filmitself on the substrate can be conducted at relatively hightemperatures.

In view of these new understandings, there is a need to preventscratch-resistant films from reducing the average flexural strength ofglass-based substrates in these articles. There is also a need to ensurethat the average flexural strength of the glass-based substrates issubstantially retained, even after high temperature exposures fromscratch-resistant film deposition processes and additionalapplication-specific thermal treatments. In addition, a need also existsfor retaining the scratch-resistance and optical properties of thesubstrate and scratch-resistant film in view of the additional design,configuration and/or processing of the interface between the substrateand the scratch-resistant film. That is, there is a need to retain, orotherwise balance, the scratch-resistance and optical properties of thearticle upon the introduction of additional interfacial features aimedat retaining strength of the article, e.g., as needed for particularapplications.

SUMMARY

A first aspect of this disclosure pertains to an article including aglass-based substrate comprising opposing major surfaces; a crackmitigating composite over one of the major surfaces, the compositecomprising an inorganic element and a polymeric element; and a hard filmdisposed on the crack mitigating composite, the film comprising anelastic modulus greater than or equal to the elastic modulus of theglass-based substrate. The crack mitigating composite is characterizedby an elastic modulus of greater than about 30 GPa. Further, the hardfilm comprises at least one of a metal-containing oxide, ametal-containing oxynitride, a metal-containing nitride, ametal-containing carbide, a silicon-containing polymer, a carbon, asemiconductor, and combinations thereof.

According to a second aspect, the article of the first aspect isprovided, wherein the article is characterized by an average flexuralstrength that is greater than or equal to about 50% of an averageflexural strength of the substrate, as measured by ring-on-ring (ROR)testing using an average from five (5) or more samples.

According to a third aspect, the article of aspect 1 or aspect 2 isprovided, wherein the hard film is further characterized by anindentation hardness of greater than or equal to about 8 GPa.

According to a fourth aspect, the article of any one of aspects 1-3 isprovided, wherein the inorganic element comprises an oxide, a nitride oran oxynitride, and the polymeric element comprises at least one of apolyimide, a polycarbonate, a polyurethane, a polyester, and afluorinated polymer.

According to a fifth aspect, the article of any one of aspects 1-4 isprovided, wherein the article is further characterized by a lighttransmissivity of greater than or equal to 50% in the visible spectrumfrom about 400 nm to about 800 nm.

According to a sixth aspect, the article of any one of aspects 1-5 isprovided, wherein the article is further characterized by a pencilhardness of 9H or greater.

According to a seventh aspect, the article of any one of aspects 1-6 isprovided, wherein article is further characterized by a delaminationthreshold of 150 mN or more, as tested using a Berkovich Ramped ScratchTest on the hard film.

According to an eighth aspect, the article of any one of aspects 1-7 isprovided, wherein the hard film comprises a multi-layer antireflectioncoating, and further wherein the crack mitigating composite and the hardfilm collectively comprise a photopic average single-side reflectance ofless than about 2%.

A ninth aspect of the disclosure pertains to an article including aglass-based substrate comprising opposing major surfaces; a crackmitigating composite over one of the major surfaces, the compositecomprising an inorganic element and a polymeric element; and a hard filmdisposed on the crack mitigating composite, the film comprising anelastic modulus greater than or equal to the elastic modulus of theglass-based substrate. The crack mitigating composite is characterizedby an elastic modulus ratio between the inorganic element and thepolymeric element of greater than 10:1. Further, the hard film comprisesat least one of a metal-containing oxide, a metal-containing oxynitride,a metal-containing nitride, a metal-containing carbide, asilicon-containing polymer, a carbon, a semiconductor, and combinationsthereof.

According to a tenth aspect, the article of aspect 9 is provided,wherein the article is characterized by an average flexural strengththat is greater than or equal to about 50% of an average flexuralstrength of the substrate, as measured by ROR testing using an averagefrom five (5) or more samples.

According to a eleventh aspect, the article of aspect 9 or aspect 10 isprovided, wherein the hard film is further characterized by anindentation hardness of greater than or equal to about 8 GPa.

According to a twelfth aspect, the article of any one of aspects 9-11 isprovided, wherein the inorganic element comprises an oxide, a nitride oran oxynitride, and the polymeric element comprises at least one of apolyimide, a polycarbonate, a polyurethane, a polyester, and afluorinated polymer.

According to a thirteenth aspect, the article of any one of aspects 9-12is provided, wherein the article is further characterized by a lighttransmissivity of greater than or equal to 50% in the visible spectrumfrom about 400 nm to about 800 nm.

According to a fourteenth aspect, the article of any one of aspects 9-13is provided, wherein the article is further characterized by a pencilhardness of 9H or greater.

According to a fifteenth aspect, the article of any one of aspects 9-14is provided, wherein the article is further characterized by adelamination threshold of 150 mN or more, as tested using a BerkovichRamped Scratch Test on the hard film.

According to a sixteenth aspect, the article of any one of aspects 9-15is provided, wherein the hard film comprises a multi-layerantireflection coating, and further wherein the crack mitigatingcomposite and the hard film collectively comprise a photopic averagesingle-side reflectance of less than about 2%.

A seventeenth aspect of the disclosure pertains to an article includinga glass-based substrate comprising opposing major surfaces; a crackmitigating composite over one of the major surfaces, the compositecomprising an inorganic element and a polymeric element; and a hard filmdisposed on the crack mitigating composite, the film comprising anelastic modulus greater than or equal to the elastic modulus of theglass-based substrate. The inorganic layer comprises an oxide, a nitrideor an oxynitride, and the polymeric layer comprises at least one of apolyimide, a polycarbonate, a polyurethane, a polyester, and afluorinated polymer. Further, the hard film comprises at least one of ametal-containing oxide, a metal-containing oxynitride, ametal-containing nitride, a metal-containing carbide, asilicon-containing polymer, a carbon, a semiconductor, and combinationsthereof.

According to an eighteenth aspect, the article of aspect 17 is provided,wherein the article is characterized by an average flexural strengththat is greater than or equal to about 50% of an average flexuralstrength of the substrate, as measured by ROR testing using an averagefrom five (5) or more samples.

According to a nineteenth aspect, the article of aspect 17 or aspect 18is provided, wherein the hard film is further characterized by anindentation hardness of greater than or equal to about 8 GPa.

According to a twentieth aspect, the article of any one of aspects 17-19is provided, wherein the at least one polymeric layer is a polyimidethat comprises PMDA-ODA, ODPA-ODA, BPDA-ODA, or a fluorinated polyimide.

According to a twenty-first aspect, the article of any one of aspects17-20 is provided, wherein the at least one inorganic layer comprisesSiO₂, Al₂O₃, ZrO₂, CaO, CaCO₃, SnO, ZnO, SiN_(x), AlN_(x), AlO_(x)N_(y),Si_(u)Al_(v)O_(x)N_(y), or SiO_(x)N_(y).

According to a twenty-second aspect, the article of any one of aspects17-21 is provided, wherein the article is further characterized by alight transmissivity of greater than or equal to 50% in the visiblespectrum from about 400 nm to about 800 nm.

According to a twenty-third aspect, the article of any one of aspects17-22 is provided, wherein the article is further characterized by apencil hardness of 9H or greater.

According to a twenty-fourth aspect, the article of any one of aspects17-23 is provided, wherein article is further characterized by adelamination threshold of 150 mN or more, as tested using a BerkovichRamped Scratch Test on the hard film.

According to a twenty-fifth aspect, the article of any one of aspects17-24 is provided, wherein the crack mitigating composite comprises twoor more inorganic layers and at least one polymeric layer, wherein oneof the two or more inorganic layers is in contact with the substrate andanother of the two or more inorganic layers is in contact with the hardfilm.

According to a twenty-sixth aspect, the article of any one of aspects17-25 is provided, wherein each of the at least one inorganic layercomprises an inorganic layer thickness and each of the at least onepolymeric layer comprises a polymeric layer thickness, and furtherwherein a ratio of the polymeric layer thickness to the inorganic layerthickness is from about 0.1:1 to about 5:1.

According to a twenty-seventh aspect, the article of any one of aspects17-26 is provided, wherein the hard film comprises a multi-layerantireflection coating, and further wherein the crack mitigatingcomposite and the hard film collectively comprise a photopic averagesingle-side reflectance of less than about 2%.

According to a twenty-eighth aspect of the disclosure, a consumerelectronic product is provided that includes: a housing having a frontsurface, a back surface and side surfaces; electrical componentsprovided at least partially within the housing, the electricalcomponents including at least a controller, a memory, and a display, thedisplay being provided at or adjacent the front surface of the housing;and a cover glass disposed over the display. Further, at least one of aportion of the housing or the cover glass comprises the article of anyone of aspects 1-27.

According to a twenty-ninth aspect of the disclosure, the article of anyone of aspects 1-27 is provided, wherein any cracked, damaged ordelaminated region associated with the at least one of the hard film andthe crack mitigating composite is less than 15 microns in length afterthe hard film is subjected to an indent from a diamond indenter at a 250mN load level during the Cube Corner Indentation Test.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an illustration of an article comprising a glass-basedsubstrate, a hard film and a crack mitigating composite, according toone or more embodiments.

FIG. 1B is an illustration of an article comprising a glass-basedsubstrate, a hard film and a crack mitigating composite comprising twoinorganic layers and a polymeric layer, according to one or moreembodiments.

FIG. 1C is an illustration of an article comprising a glass-basedsubstrate, a hard film and a crack mitigating composite comprising threeinorganic layers and two polymeric layers, according to one or moreembodiments.

FIG. 2 is a schematic diagram of the development of a crack in a film orlayer and its possible bridging modes.

FIG. 3 is an illustration of a theoretical model for the presence of acrack in a film or layer and its possible bridging paths.

FIG. 4 is a diagram illustrating the energy release ratio G_(d)/G_(p).

FIG. 5A is a schematic diagram of a cohesive failure in a crackmitigating composite interposed between a hard film and a glass-basedsubstrate according to some embodiments of this disclosure.

FIG. 6A is a plot of elastic modulus of a crack mitigating composite, asdisposed on a glass-based substrate, as a function of the ratio of thethickness of the polymeric layer in the composite to the thickness ofthe complete crack mitigating composite, as measured according to ananoindentation method, according to some embodiments of the disclosure.

FIG. 6B is a plot of hardness of a crack mitigating composite, asdisposed on a glass-based substrate, as a function of the ratio of thethickness of the polymeric layer in the composite to the thickness ofthe complete crack mitigating composite, as measured according to ananoindentation method, according to some embodiments of the disclosure.

FIG. 7 is a scanning electron microscope (SEM) image from across-section of an article comprising a glass-based substrate, a hardfilm and a crack mitigating composite comprising two inorganic layersand two polymeric layers according to some embodiments of thisdisclosure.

FIG. 8 is a graph presenting ring-on-ring load-to-failure performance ofa glass-based substrate control (Example 1C); articles comprisingglass-based substrates (1 mm and 0.7 mm thick) having silicon nitridehard films (440 μm thick) (Examples 1A and 1A1, respectively); andarticles comprising glass-based substrates (1 mm and 0.7 mm thick)having a silicon nitride hard film (440 μm) and a five-layer crackmitigating composite (Examples 1B and 1B1, respectively) according toaspects of this disclosure.

FIGS. 9A-9D are optical microscopy images from articles comprisingglass-based substrates having a hard film comprising a silicon nitridelayer and a fluorosilane layer, and no crack mitigating composite (9A),a crack mitigating composite comprising three thick alumina and two thinpolyimide layers (9B), a crack mitigating composite comprising threethin alumina and two thick polyimide layers (9C), or a crack mitigatingcomposite comprising polyimide (9D).

FIG. 10 is a graph presenting optical transmittance data as a functionof wavelength in the visible spectrum for articles comprising aglass-based substrate and a silicon nitride hard film, with no crackmitigating composite (Ex. 2C), a crack mitigating composite comprising apolyimide (Exs. 2B1, 2B2) and a crack mitigating composite comprisingalumina and polyimide layers (Ex. 2A), according to some embodiments ofthe disclosure.

FIGS. 11A and 11B are atomic force microscopy (AFM) images for articlescomprising a glass-based substrate, a silicon nitride hard film and acrack mitigating composite comprising alumina and polyimide layers (11A)and no crack mitigating composite (11B), according to some embodimentsof the disclosure.

FIG. 12A is an optical microscopy image from an article comprising aglass-based substrate, a silicon nitride hard film and a barium fluoridecrack mitigating composite, as subjected to a Berkovich ramped scratchtest (0 to 150 mN).

FIG. 12B is an optical microscopy image from an article, according tosome embodiments of the disclosure, comprising a glass-based substrate,a silicon nitride hard film and a crack mitigating composite comprisingalumina and polyimide layers, as subjected to a Berkovich ramped scratchtest (0 to 150 mN).

FIGS. 13A and 13B provide two-surface transmittance (i.e., as includingboth sides of the coated laminated article) and first-surfacereflectance (i.e., as considering only the coated side of the laminatedarticle) modeled optical data, respectively, as developed on a laminatearticle configured with a five-layer Al₂O₃/polyimide crack mitigatingcomposite and a SiO₂/AlO_(x)N_(y) scratch-resistant film, according toan embodiment of the disclosure.

FIGS. 14A and 14B provide two-surface transmitted color andfirst-surface reflected color modeled optical data, respectively, asdeveloped on a laminate article configured with a five-layerAl₂O₃/polyimide crack mitigating composite and a SiO₂/AlO_(x)N_(y)scratch-resistant film, according to an embodiment of the disclosure.

FIG. 15 provides first-surface photopic reflectance modeled opticaldata, as developed on a laminate article configured with a five-layerAl₂O₃/polyimide crack mitigating composite and a SiO₂/AlO_(x)N_(y)scratch-resistant film, according to an embodiment of the disclosure.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details may beset forth in order to provide a thorough understanding of embodiments ofthe disclosure. However, it will be clear to one skilled in the art whenembodiments of the disclosure may be practiced without some or all ofthese specific details. In other instances, well-known features orprocesses may not be described in detail so as not to unnecessarilyobscure the disclosure. In addition, like or identical referencenumerals may be used to identify common or similar elements.

As used herein, the term “about” means that amounts, sizes,formulations, parameters, and other quantities and characteristics arenot and need not be exact, but may be approximate and/or larger orsmaller, as desired, reflecting tolerances, conversion factors, roundingoff, measurement error and the like, and other factors known to those ofskill in the art. When the term “about” is used in describing a value oran end-point of a range, the disclosure should be understood to includethe specific value or end-point referred to. Whether or not a numericalvalue or end-point of a range in the specification recites “about,” thenumerical value or end-point of a range is intended to include twoembodiments: one modified by “about,” and one not modified by “about.”It will be further understood that the endpoints of each of the rangesare significant both in relation to the other endpoint, andindependently of the other endpoint.

The terms “substantial,” “substantially,” and variations thereof as usedherein (except when used in “substantially no peeling” which is definedelsewhere) are intended to note that a described feature is equal orapproximately equal to a value or description. For example, a“substantially planar” surface is intended to denote a surface that isplanar or approximately planar. Moreover, as defined above,“substantially similar” is intended to denote that two values are equalor approximately equal. In some embodiments, “substantially similar” maydenote values within about 10% of each other, such as within about 5% ofeach other, or within about 2% of each other.

Directional terms as used herein—for example up, down, right, left,front, back, top, bottom—are made only with reference to the figures asdrawn and are not intended to imply absolute orientation.

As used herein the terms “the,” “a,” or “an,” mean “at least one,” andshould not be limited to “only one” unless explicitly indicated to thecontrary. Thus, for example, reference to “a component” includesembodiments having two or more such components unless the contextclearly indicates otherwise.

As used herein the term “glass-based” is meant to include any materialmade at least partially of glass, including glass and glass-ceramics,and sapphire. “Glass-ceramics” include materials produced throughcontrolled crystallization of glass. In embodiments, glass-ceramics haveabout 1% to about 99% crystallinity. Non-limiting examples of glassceramic systems that may be used include Li₂O×Al₂O₃×nSiO₂ (i.e. LASsystem), MgO×Al₂O₃×nSiO₂ (i.e. MAS system), and ZnO×Al₂O₃×nSiO₂ (i.e.ZAS system).

Referring to FIG. 1A, aspects of this disclosure include a laminatearticle 100 a having a total stack thickness 10 a. The article 100 aalso includes a hard film 110 with a thickness 11, a glass-basedsubstrate 120 with a thickness 12 and a crack mitigating composite 130 awith a thickness 13 a comprising an inorganic element 33 and a polymericelement 35. In these aspects, the crack mitigating composite 130 aincludes an inorganic element 33 and a polymeric element 35, either orboth in the form of one or more layers, films, or other structures, suchas particulate, fibers and/or whiskers. Further, the crack mitigatingcomposite 130 a, inclusive of its inorganic and polymer elements 33, 35,is characterized by an elastic modulus of greater than 30 GPa. Forexample, the crack mitigating composite 130 a can be characterized by anelastic modulus of 30.5 GPa, 31 GPa, 32 GPa, 33 GPa, 34 GPa, 35 GPa, 40GPa, 45 GPa, 50 GPa, and so on, including all elastic modulus valuesbetween these levels, and conceivably up to 80 GPa and even approaching120 GPa in some cases.

According to some embodiments of the laminate article 100 a, the crackmitigating composite 130 a includes an inorganic element 33 and apolymeric element 35, with greater than about 20% by volume of materialassociated with the inorganic element 33 and greater than about 0.5% ormore by volume of material associated with the polymeric element 35. Forexample, the amount of material associated with the inorganic element 35can be greater than about 20%, 30%, 40%, 50%, 60% by volume, and allamounts between these volumetric levels. Preferably, the polymericelement 35 comprises polymeric material having C—C, C—N, C—O and/or C═Cbonds as polymeric chain-forming bonds. Further, in some embodiments,the crack mitigating composite 130 a can have a compositecrack-onset-strain (COS) value of greater than about 0.8%, greater than1%, greater than about 1.5%, and all COS values between or above theselevels.

COS on a glass substrate is measured in a ring-on ring setup linked to acamera system. More specifically, to determine the strain-to-failure ofthe coated article 100, force is applied to the top ring 304 in adownward direction and/or to the bottom ring in an upward direction in aring-on-ring mechanical testing device. According to the Ring-on-RingTensile Testing Procedure, the article 100 is positioned between thebottom ring and the top ring. The top ring and the bottom ring havedifferent diameters. As used herein, the top ring has a diameter of 12.7mm and the bottom ring as a diameter of 25.4 mm. The portion of the topring and bottom ring which contact the article are circular in crosssection and each have radius of 1.6 mm. The top ring and bottom ring aremade of steel. Testing is performed in an environment of about 22° C.with 45%-55% relative humidity. The articles used for testing are 50 mmby 50 mm square in size. The force on the top ring and or bottom ring isincreased, causing strain in the article 100 until catastrophic failureof one or both of the substrate and any optical coating. A light andcamera are provided below the bottom ring to record the catastrophicfailure during testing. An electronic controller, such as a Dewetronacquisition system, is provided to coordinate the camera images with theapplied load to determine the load when catastrophic damage is observedby the camera. To determine the strain-to-failure, camera images andload signals are synchronized through the Dewetron system, so that theload at which the coating and/or substrate shows failure can bedetermined. Then, finite element analysis is used to analyze the strainlevels the sample is experiencing at this load. The element size may bechosen to be fine enough to be representative of the stressconcentration underneath the loading ring. The strain level is averagedover 30 nodal points or more underneath the loading ring. Furthermore,testing techniques to determine load-to-failure may be found in “Hu, G.,et al., Dynamic fracturing of strengthened glass under biaxial tensileloading. Journal of Non-Crystalline Solids, 2014. 405(0): p. 153-158.)”

Further, in some embodiments of the laminate article 100 a, the crackmitigating composite 130 a can be characterized by an elastic modulusratio between the inorganic element 33 and the polymeric element 35 ofgreater than 10:1 (e.g., an inorganic element 33 with an elastic modulusof 150 GPa and a polymeric element with an elastic modulus of 10 GPawould result in an elastic modulus ratio of 15:1). For example, theelastic modulus ratio of the crack mitigating composite 130 a can be11:1, 12:1, 13:1, 14:1, 15:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1,90:1, 100:1 and all elastic modulus ratios between or above theseratios. According to some embodiments, a practical elastic modulus ratiolimit for the crack mitigating composite 130 a is about 500:1 forcertain very low elastic modulus polymeric elements 35 (e.g., <1 GPa)coupled with relatively high elastic modulus inorganic elements 33(e.g., >75 GPa) incorporated within the crack mitigating composite 130a.

Further, the hard film 110 of the laminate article 100 a comprises atleast one of a metal-containing oxide, a metal-containing oxynitride, ametal-containing nitride, a metal-containing carbide, asilicon-containing polymer, a carbon, a semiconductor, and combinationsthereof. In some embodiments of the laminate article 100 a, the hardfilm 110 comprises silicon nitride or silicon dioxide. In certainaspects, the hard film 110 can be further characterized by anindentation hardness of greater than or equal to about 8 GPa. In otherembodiments, the hard film 110 can be characterized by an indentationhardness of greater than or equal to about 12 GPa. Accordingly, the hardfilm 110 can be characterized by an indentation hardness of 8 GPa, 9GPa, 10 GPa, 11 GPa, 12 GPa, 13 GPa, 14 GPa, 15 GPa, 20 GPa, 25 GPa, 30GPa and all indentation hardness values between or above these levels.According to some embodiments, a practical limit for the indentationhardness of the hard film 110 is about 50 GPa.

Within the article 100 a, the interfacial properties at an effectiveinterface 140 between the hard film 110 and the crack mitigatingcomposite 130 a or the crack mitigating composite 130 a and thesubstrate 120 are modified, generally by virtue of the crack mitigatingcomposite 130 a, such that the article 100 a substantially retains itsaverage flexural strength, and the film 110 retains functionalproperties for its application, particularly scratch resistance. Forexample, in some embodiments of the laminate article 100 a, the articleis characterized by an average flexural strength that is greater than orequal to about 50% of an average flexural strength of theglass-substrate (i.e., as tested without a crack mitigating composite130 a and hard film 110 structures disposed thereon). In otherembodiments, the flexural strength of the article 100 a that comprisesthe crack mitigating composite 130 a may be characterized by comparisonto a similar article comprising the same hard film 110 and the sameglass substrate 120, but no crack mitigating composite structure. Inthese embodiments, the article 100 a that comprises the crack mitigatingcomposite 130 a may have an average or characteristic flexural strengththat is 25% greater, or 50% greater, than the same article without thecrack mitigating composite (i.e., a comparison article in which the hardfilm 110 is deposited directly over the substrate 120).

Referring now to FIG. 1B, aspects of this disclosure include a laminatearticle 100 b having a total stack thickness 10 b. The article 100 balso includes a hard film 110, a glass-based substrate 120, and a crackmitigating composite 130 b having a total thickness 13 b and comprisingan inorganic element 33 and a polymeric element 35. The laminate article100 b is similar to the laminate article 100 a; consequently,like-numbered elements have the same or similar structure andfunction(s) (e.g., the hard film 110). Further, as shown in FIG. 1B, thecrack mitigating composite 130 b can include an inorganic element 33 inthe form of one or more layers, and a polymeric element 35 in the formof one or more layers. As shown in exemplary form in FIG. 1B, thelaminate article 100 b has an inorganic element 33 with two layers and apolymeric element 35 with one layer interposed between the layers of theinorganic element 33. As also shown in FIG. 1B, one of the layers of theinorganic element 33 is in contact with the glass-based substrate 120and the other layer of the inorganic element 33 is in contact with thehard film 110. As also shown in FIG. 1B, each of the layers of theinorganic element 33 has a thickness 63 and each of the layers of thepolymeric element 35 has a thickness 65. Additionally, the thickness ofeach layer may be the same as the other layers, or may be differenttherefrom.

Further, the crack mitigating composite 130 b, inclusive of itsinorganic and polymer elements 33, 35 in the form of layers, ischaracterized by an elastic modulus of greater than 30 GPa. For example,the crack mitigating composite 130 b can be characterized by an elasticmodulus of 30.5 GPa, 31 GPa, 32 GPa, 33 GPa, 34 GPa, 35 GPa, 40 GPa, 45GPa, 50 GPa, and so on, including all elastic modulus values betweenthese levels, and conceivably up to 80 GPa and even approaching 120 GPain some cases. As described herein, the “elastic modulus” or “averageelastic modulus” of the crack mitigating composite 130 b, inclusive ofits inorganic and polymer elements 33, 35 in the form of layers, iscalculated by taking the measured values of each layer of the inorganicand polymeric elements 33, 35, as measured on a single film basis on theorder of 100 nm to 1000 nm in thickness and then calculating avolumetric average elastic modulus for the crack mitigating composite130 b. In addition, the volumetric average elastic modulus can becalculated as understood by those with ordinary skill in the field ofthe disclosure, e.g., in view of volumetric estimates or actualvolumetric measurements for each of the layers of the inorganic andpolymeric elements 33, 35. In addition, the modulus of the crackmitigating composite, which may comprise layers, can be an effective orempirical modulus that is directly measured on the composite using knownnanoindentation methods sampling a volume of the composite structurethat effectively averages together the moduli of the organic andinorganic layer components.

According to some embodiments of the laminate article 100 b, the crackmitigating composite 130 b includes an inorganic element 33 comprisingone or more layers and a polymeric element 35 comprising one or morelayers, with greater than about 20% by volume of material associatedwith the inorganic element 33 and greater than about 0.5% or more byvolume of material associated with the polymeric element 35. Forexample, the amount of material associated with the inorganic element 35can be greater than about 20%, 30%, 40%, 50%, 60% by volume, and allamounts between these volumetric levels. Preferably, the polymericelement 35 comprises polymeric material having C—C, C—N, C—O and/or C═Cbonds as polymeric chain-forming bonds. Further, in some embodiments,the crack mitigating composite 130 b can have a compositecrack-onset-strain (COS) value of greater than about 0.8%, greater than1%, greater than about 1.5%, and all COS values between or above theselevels.

Further, in some embodiments of the laminate article 100 b, the crackmitigating composite 130 b can be characterized by an elastic modulusratio between the inorganic element 33 and the polymeric element 35(i.e., as inclusive of their respective layers) of greater than 10:1(e.g., an inorganic element 33 with two layers, each having an elasticmodulus of 150 GPa, and a polymeric element having one layer with anelastic modulus of 10 GPa would result in an elastic modulus ratio of15:1). For example, the elastic modulus ratio of the crack mitigatingcomposite 130 b can be 11:1, 12:1, 13:1, 14:1, 15:1, 20:1, 30:1, 40:1,50:1, 60:1 70:1, 80:1, 90:1, 100:1, and all elastic modulus ratiosbetween or above these ratios. According to some embodiments, apractical elastic modulus ratio limit for the crack mitigating composite130 b is about 500:1 for certain very low elastic modulus polymericelements 35 (e.g., <1 GPa) coupled with relatively high elastic modulusinorganic elements 33 (e.g., >75 GPa) incorporated within the crackmitigating composite 130 b.

Referring again to FIG. 1B, the crack mitigating composite 130 b of thelaminated article 100 b includes an inorganic element 33 with one ormore layers having a thickness 63. In some aspects, the thickness 63 ofeach layer of the inorganic element 33 can range from about 1 nm toabout 200 nm, preferably from about 5 nm to about 150 nm. Further, insome aspects, the thickness 65 of each layer of the polymeric element 35can range from about 1 nm to about 500 nm, preferably from about 5 nm toabout 300 nm. According to another implementation, the total thickness13 b of the crack mitigating composite 130 b can range from about 10 nmto about 1000 nm. In a preferred aspect, the total thickness 13 b of thecrack mitigating composite 130 b ranges from about 50 nm to about 750nm.

In some implementations, the laminate article 100 b can include a crackmitigating composite 130 b governed by a thickness ratio for the layersof its inorganic and polymeric elements 33, 35. For example, a ratiobetween the total thickness of the polymeric element 35 (i.e., the sumof the thickness 65 values for each of its layers) and the inorganicelement 33 (i.e., the sum of the thickness 63 values for each of itslayers) can be from about 0.1:1 to about 5:1. In other implementations,the thickness ratio can be about 0.2:1 to about 3:1. As also understoodherein, the implementations of the laminate article 100 b and crackmitigating composite 130 b governed by such thickness ratios areconfigured such that the thickness ratios are calculated independent ofany additional layers added to the crack mitigating composite 130 bimmediately adjacent to one or both of the hard film 110 and/orglass-based substrate 120. Such layers, as described herein, arereferred to as “tie layers” and are typically one half to an order (ororders) of magnitude thinner than the other layers of the inorganic andpolymeric elements 33, 35.

Within the article 100 b, the interfacial properties at an effectiveinterface 140 between the hard film 110 and the crack mitigatingcomposite 130 b or between the crack mitigating composite 130 b and thesubstrate 120 are modified, generally by virtue of the crack mitigatingcomposite 130 b, such that the article 100 b substantially retains itsaverage flexural strength, and the hard film 110 retains functionalproperties for its application, particularly scratch-resistance. Forexample, in some embodiments of the laminate article 100 b, the articleis characterized by an average flexural strength that is greater than orequal to about 70% of an average flexural strength of theglass-substrate (i.e., as tested without a crack mitigating composite130 b and hard film 110 structures disposed thereon).

As understood in this disclosure, the terms “hard film,”“scratch-resistant film” and the “hard film 110” can include one or morefilms, layers, structures and combinations thereof. Further, the hardfilm 110 can, in some aspects, include additional functional filmsincluding but not limited to fingerprint resistant coatings,smudge-resistant coatings, easy-to-clean coatings, coatings with lowsurface energies, and fluorosilane-based coatings. It should also beunderstood that for a “film” that includes more than one film, layer,structure, etc., the refractive index associated with the “film” is theaggregate or composite refractive index of the films, layers,structures, etc. that make up the “film.”

Referring now to FIG. 1C, aspects of this disclosure include a laminatearticle 100 c having a total stack thickness 10 c. The article 100 calso includes a hard film 110, a glass-based substrate 120, and a crackmitigating composite 130 c having a total thickness 13 c and comprisingan inorganic element 33 and a polymeric element 35. The laminate article100 c is similar to the laminate article 100 b; consequently,like-numbered elements have the same or similar structure andfunction(s) (e.g., the hard film 110). Further, as shown in FIG. 1C, thecrack mitigating composite 130 c of the laminate article 100 c isdepicted in an exemplary, preferred form. In particular, the crackmitigating composite 130 c includes an inorganic element 33 in the formof three layers, preferably comprising Al₂O₃, and a polymeric element 35in the form of two layers, preferably comprising a polyimide. As alsoshown in FIG. 1C, one of the layers of the inorganic element 33 is incontact with the glass-based substrate 120 and one of the other layersof the inorganic element 33 is in contact with the hard film 110. Asalso shown in FIG. 1C, each of the layers of the inorganic element 33has a thickness 62, preferably from about 1 nm to about 200 nm, and eachof the layers of the polymeric element 35 has a thickness 65, preferablyabout 1 nm to about 500 nm.

Referring again to FIGS. 1A-1C, aspects of this disclosure include alaminate article 100 a, 100 b, 100 c including a glass-based substrate120 and a crack mitigating composite 130 a, 130 b, 130 c. Within thearticle 100 a, 100 b, 100 c, the interfacial properties at an effectiveinterface 140 between the crack mitigating composite 130 a, 130 b, 130 cand the substrate 120 are modified such that the article 100 a, 100 b,100 c substantially retains its average flexural strength. In furtherembodiments, the interfacial properties at an effective interface 140between the crack mitigating composite 130 a, 130 b, 130 c and thesubstrate 120 are modified such that the article 100 a, 100 b, 100 csubstantially retains 50% or more, 60% or more, 70% or more, 80% ormore, 90% or more, or 95% or more of its average flexural strength. Inadditional implementations, the interfacial properties at the effectiveinterface 140 are modified such that the article 100 a, 100 b, 100 csubstantially retains its scratch resistance, particularly the scratchresistance associated with the hard film 110.

In one or more embodiments, the laminate article 100 a, 100 b, 100 cexhibits functional properties that are also retained after suchinterface modifications, e.g., scratch resistance. Functional propertiesof the hard film 110 and/or articles 100 a, 100 b, 100 c may includeoptical properties, electrical properties and/or mechanical properties,for example hardness, elastic modulus, strain-to-failure, abrasionresistance, scratch resistance, mechanical durability, coefficient offriction, electrical conductivity, electrical resistivity, electronmobility, electron or hole carrier doping, optical refractive index,density, opacity, transparency, reflectivity, absorptivity,transmissivity and the like.

In one or more embodiments, the refractive index may be measured usingan Model 1512-RT analyzer, supplied by n&k Technology, Inc., located inSan Jose, Calif., or by spectroscopic ellipsometry, as is known in theart. Elastic modulus may be measured by nanoindentation, using methodsknown in the art according to those skilled in the field of thedisclosure. In certain implementations, the optical properties of thearticles 100 a, 100 b, 100 c are retained, independent of the propertiesand/or processing of the crack mitigating composite 130 a, 130 b, 130 c.In certain aspects, the optical transmittance of the glass-basedsubstrate 120 and the crack mitigating composite 130 a, 130 b, 130 c canvary by 1% or less from the optical transmittance of the substrate 120(e.g., from wavelengths of 400 nm to 800 nm). In other aspects, theoptical transmittance of the laminated article 100 a, 100 b, 100 c canbe characterized by a light transmissivity of greater than or equal to50% in the visible spectrum from about 400 nm to about 800 nm, or fromabout 450 to about 650 nm. In other aspects, the optical transmittanceof the laminated article 100 a, 100 b, 100 c can be characterized by alight transmissivity of greater than or equal to 20%, 50% or 80% in thevisible spectrum. These functional properties of the articles 100 a, 100b, 100 c can be retained after combination with the crack mitigatingcomposite 130 a, 130 b, 130 c, and before any separation of the crackmitigating composite 130 a, 130 b, 130 c from the glass-based substrate120 as described herein.

The advantageous properties of the articles 100 a-100 c can also becharacterized the Cube Corner Indentation Test. In particular, the CubeCorner Indentation Test uses a diamond indenter tip shaped as the cornerof a cube, which is pushed down into the surface of the film, structureor other feature to be measured. With regard to the articles 100 a-c ofthe disclosure, it is beneficial to quantify delamination and crackingthresholds which are related to scratch performance of the articles inreal world applications. These properties can be quantified by theseverity and/or area of the damaged surface after loading and unloadingby the cube corner indenter during the Cube Corner Indentation Test.These scratch resistance-related properties can also be quantified bymonitoring the load vs. displacement curve during the loading phase inthe Cube Corner Indentation Test for discontinuous jumps, which are anindication of the starting point of crack at certain loading conditions.Both of these approaches can be used to quantify a threshold forcracking or delamination events. For example in embodiments of thearticles 100 a-c, a cracked, delaminated and/or chipped area (i.e., asassociated with the hard film and/or the crack mitigating composite)after the Cube Corner Indentation can be less than 15 microns in lengthfrom the center of the indent at a 250 mN load level and less than 30microns in length from the center of the indent at a 400 mN load level.Additionally, discontinuities in the load vs. displacement curve thatresults from the Cube Corner Indentation Test can occur during loadingat loads greater than 200 mN (with no significant discontinuitiesobserved at loads less than 200 mN) during loading with the indenter inthe Cube Corner Indentation Test.

In one or more embodiments, the laminate article 100 a, 100 b, 100 ccomprising a crack mitigating composite 130 a, 130 b, 130 c and a hardfilm 110 can exhibit a substantial retained scratch resistance, asjudged relative to the scratch-resistance of the same film 110 disposeddirectly on a glass-based substrate 120 without a comparable crackmitigating composite. For example, the laminate article 100 a, 100 b,100 c can exhibit no evidence of delamination when subjected to aBerkovich Ramped Test from scratch loads ranging from 0 mN up to 150 mNas a stylus is moved from left to right (or vice versa) over eachsample. In particular, in the Berkovich Ramped Scratch Test, a Berkovichdiamond indenter is scratched (leading with the corner of the indentertip) across the surface of the laminate article 100 a, 100 b, 100 c withan increasing load from 0 mN to 150 mN, ramped in a linear fashion overa length of 1500 microns and at a velocity of 15 microns/second (1.5mN/sec). The onset of delamination (e.g., between a hard film and anunderlying crack mitigating composite and/or glass-based substrate) isdetermined using an optical microscope and correlating the location onthe scratch where delamination starts to the indenter load level at theonset of delamination.

As another example, the laminate article 100 a, 100 b, 100 c comprisinga crack mitigating composite 130 a, 130 b, 130 c and a hard film 110 canexhibit a substantial retained scratch resistance as determined throughpencil hardness measurements, as judged relative to thescratch-resistance of the same film 110 disposed directly on aglass-based substrate 120 without a comparable crack mitigatingcomposite. In particular, pencil hardness testing on laminate articles100 a-c can be conducted according to the ASTM D3363 test method. Thepencil is placed in an angled holder and scratched across the surface ofthe laminate article 100 a-c on the side of the hard film 110 withenough force to crush the graphite of the pencil. Accordingly, themaximum pencil hardness value in the ASTM D3363 test is associated withthe hardest common pencil, a 9H pencil. In some implementations, thelaminate article 100 a-c is further characterized by a pencil hardnessof 9H or greater.

In one or more embodiments of laminate articles 100 a, 100 b, 100 c, themodification to the effective interface 140 between the hard film 110and the glass-based substrate 120 includes preventing one or more cracksfrom bridging from one of the film 110 or the glass-based substrate 120into the other of the film 110 or the glass-based substrate 120, whilepreserving other functional properties of the film 110 and/or thearticle. In one or more specific embodiments, as illustrated in FIGS.1A, 1B and 1C, the modification of the interfacial properties includesdisposing a crack mitigating composite 130 a, 130 b, 130 c between theglass-based substrate 120 and the hard film 110. In one or moreembodiments, the crack mitigating composite 130 a, 130 b, 130 c isdisposed on the glass-based substrate 120 and forms a first interface150, and the film 110 is disposed on the crack mitigating composite 130a, 130 b, 130 c forming a second interface 160. The effective interface140 includes the first interface 150, the second interface 160 and/orthe crack mitigating composite 130 a, 130 b, 130 c.

With regard to the laminate articles 100 a-c depicted in FIGS. 1A-1C,the term “hard film,” as applied to the hard film 110 and/or other filmsincorporated into the article 100 a, 100 b, 100 c, includes one or morelayers that are formed by any known method in the art, includingdiscrete deposition or continuous deposition processes. Such layers ofthe hard film may be in direct contact with one another. The layers maybe formed from the same material or more than one different material. Inone or more alternative embodiments, such layers may have interveninglayers of different materials disposed therebetween. In one or moreembodiments a hard film 110 may include one or more contiguous anduninterrupted layers and/or one or more discontinuous and interruptedlayers (i.e., a layer having different materials formed adjacent to oneanother).

As used herein (e.g., in relation to laminate articles 100 a, 100 b, 100c), the term “dispose” includes coating, depositing and/or forming amaterial onto a surface using any known method in the art. The disposedmaterial may constitute a layer or film as defined herein. The phrase“disposed on” includes the instance of forming a material onto a surfacesuch that the material is in direct contact with the surface and alsoincludes the instance where the material is formed on a surface, whereone or more intervening material(s) is between the disposed material andthe surface. The intervening material(s) may constitute a layer or film,as defined herein.

As used herein, the term “average flexural strength” is intended torefer to the flexural strength of a glass-containing material (e.g., anarticle and/or a glass-based substrate), as tested through methods ofring-on-ring (also referred herein as “ROR”) testing. The term “average”when used in connection with average flexural strength or any otherproperty is based on the mathematical average of measurements of such aproperty on 5 samples or more. Average flexural strength may refer tothe scale parameter of two parameter Weibull statistics of failure loadunder ring-on-ring testing. This scale parameter is also called theWeibull characteristic strength, at which a material's failureprobability is 63.2%. More broadly, average flexural strength may alsobe defined by other tests, for example, a ball drop test, where theglass surface flexural strength is characterized by a ball drop heightthat can be tolerated without failure. Glass surface strength may alsobe tested in a device configuration, where an appliance or devicecontaining the glass-containing material (e.g., an article and/or aglass-based substrate) article is dropped in different orientations thatmay create a surface flexural stress. Average flexural strength may insome cases also incorporate the strength as tested by other methodsknown in the art, for example 3-point bend or 4-point bend testing. Insome cases, these test methods may be significantly influenced by theedge strength of the article.

As used herein, the terms “bridge” and “bridging” are interchangeable,and refer to crack, flaw or defect formation and such crack, flaw ordefect's growth in size and/or propagation from one material, layer orfilm into another material, layer or film. For example, bridgingincludes the instance where a crack that is present in the hard film 110propagates into another material, layer or film (e.g., the glass-basedsubstrate 120). The terms “bridge” or “bridging” also include theinstance where a crack crosses an interface between different materials,different layers and/or different films. The materials, layers and/orfilms need not be in direct contact with one another for a crack tobridge between such materials, layers and/or films. For example, thecrack may bridge from a first material into a second material, not indirect contact with the first material, by bridging through anintermediate material disposed between the first and second material.The same scenario may apply to layers and films and combinations ofmaterials, layers and films. In the laminate articles 100 a, 100 b, 100c, as described herein (see FIGS. 1A-1C), a crack may originate in oneof the hard film 110 or the glass-based substrate 120 and bridge intothe other of the hard film 110 or the glass-based substrate 120 acrossthe effective interface 140 (and specifically across the first interface150 and the second interface 160).

As will be described herein in connection with the laminate articles 100a, 100 b, 100 c, the crack mitigating composite 130 a, 130 b, 130 c maydeflect cracks from bridging between the hard film 110 and theglass-based substrate 120, regardless of where the crack originates(i.e., the film 110 or the glass-based substrate 120). Likewise, thecrack mitigating composite 130 a, 130 b, 130 c of the laminate articles100 a, 100 b, 100 c may deflect cracks from bridging between the crackmitigating composite 130 a, 130 b, 130 c and the glass-based substrate120. Crack deflection may include at least partial delamination of thecrack mitigating composite 130 a, 130 b, 130 c from the film 110 and/orglass-based substrate 120, as described herein, upon bridging of thecrack from one material (e.g., the film 110, glass-based substrate 120or crack mitigating composite 130 a, 130 b, 130 c) to another material(e.g., the film 110, glass-based substrate 120 or crack mitigatingcomposite 130 a, 130 b, 130 c). Crack deflection may also includecausing a crack to propagate through the crack mitigating composite 130a-c instead of propagating into the film 110 and/or the glass-basedsubstrate 120. In such instances, the crack mitigating composite 130 a-cmay form a low toughness interface at the effective interface 140 thatfacilitates crack propagation through the crack mitigating compositeinstead of into the glass-based substrate or film. This type ofmechanism may be described as deflecting the crack along the effectiveinterface 140.

The following theoretical fracture mechanics analysis illustratesselected ways in which cracks may bridge or may be mitigated within alaminated article, e.g., laminate articles 100 a, 100 b, 100 c (seeFIGS. 1A-1C). FIG. 2 is a schematic illustrating the presence of a crackin a film disposed on a glass-based substrate and its possible bridgingor mitigation modes. The numbered elements in FIG. 2 are the glass-basedsubstrate 40 (e.g., comparable to the glass-based substrate 120 in FIGS.1A-1C), the film 42 (e.g., comparable to the hard film 110) on top of asurface (unnumbered) of glass-based substrate 40, a two-sided deflection44 into the interface between glass-based substrate 40 and film 42, anarrest 46 (which is a crack that started to develop in film 42 but didnot go completely through film 42), a “kinking” 48 (which is a crackthat developed in the surface of film 42, but when it reached thesurface of the glass-based substrate 40 it did not directly penetrateinto the glass-based substrate 40, but instead moves in a lateraldirection as indicated in FIG. 2 and then penetrates the surface of theglass-based substrate 40 at another position), a penetration crack 41that developed in the film 42 and penetrated into the glass-basedsubstrate 40, and a one-sided deflection 43. FIG. 2 also shows a graphof tension vs. compression (i.e., element 47) in the glass-basedsubstrate 40 compared to a zero axis (i.e., element 45) as may beinduced by the glass-based substrate 40 by chemical and/or thermaltempering, wherein surfaces of the glass-based substrate are incompression (including compressive stress), and a central portion is intension (including tensile stress). Hence, the portion of element 47 tothe right of the zero axis (i.e., element 45) is indicative ofcompressive stress and the portion of element 47 to the left of the zeroaxis is indicative of tensile stress. As illustrated, upon applicationof external loading (in such cases, tensile loading is the mostdetrimental situation), the flaws in the film can be preferentiallyactivated to form cracks (e.g., crack deflection 44) prior to thedevelopment of cracks in the residually compressed or strengthenedglass-based substrate 40. In the scenarios illustrated in FIG. 2, withcontinued increase of external loading, the cracks will bridge untilthey encounter the glass-based substrate. When the cracks, uponorigination in the film 42, reach the surface of glass-based substrate40, the possible bridging modes of the crack are: (a) penetration intothe glass-based substrate without changing its path as represented bynumeral 41; (b) deflection into one side along the interface between thefilm and the glass-based substrate as indicated by numeral 43; (c)deflection into two sides along the interface as indicated by numeral44; (d) first deflection along the interface and then kinking into theglass-based substrate as indicated by numeral 48; or (e) crack arrest asindicated by numeral 46 due to microscopic deformation mechanisms, forexample, plasticity, nano-scale blunting, or nano-scale deflection atthe crack tip. Cracks may originate in the film and may bridge into theglass-based substrate. The above-described bridging modes are alsoapplicable where cracks originate in the glass-based substrate andbridge into the film, for example where pre-existing cracks or flaws inthe glass-based substrate may induce or nucleate cracks or flaws in thefilm, thus leading to crack growth or propagation from the glass-basedsubstrate into the film, resulting in crack bridging.

Crack penetration into the glass-based substrate 120 and/or hard film110 reduces the average flexural strength of the laminated articles 100a, 100 b, 100 c (see FIGS. 1A-1C) and the glass-based substrate 120 ascompared to the average flexural strength of the glass-based substrate120 alone (i.e., without a hard film 110 and/or a crack mitigatingcomposite 130 a-c), while crack deflection, crack blunting or crackarrest (collectively referred to herein as crack mitigation) helpsretain the average flexural strength of the articles. “Crack blunting”and “crack arrest” can be distinguished from one another. “Crackblunting” may comprise an increasing crack tip radius, for example,through plastic deformation or yielding mechanisms. “Crack arrest,” onthe other hand, could comprise a number of different mechanisms, forexample, encountering a highly compressive stress at the crack tip; areduction of the stress intensity factor at the crack tip resulting fromthe presence of a low-elastic modulus interlayer or a low-elasticmodulus-to-high-elastic modulus interface transition; nano-scale crackdeflection or crack tortuosity as in some polycrystalline or compositematerials; and strain hardening at the crack tip, and the like. Thevarious modes of crack deflection will be described herein.

Without being bound by theory, certain possible crack bridging paths canbe analyzed in the context of linear elastic fracture mechanics. In thefollowing paragraphs, one crack path is used as an example and thefracture mechanics concept is applied to the crack path to analyze theproblem and illustrate the desired material parameters to help retainthe average flexural strength performance of the article for aparticular range of material properties.

FIG. 3 shows the illustration of the theoretical model framework. Thisis a simplified schematic view of the interface region between the film52 (e.g., film 52 is comparable to the hard film 110 in laminatearticles 100 a-100 c) and glass-based substrate 50 (e.g., the substrate40 is comparable to the glass-based substrate 120 in the laminatearticles 100 a-100 c). The terms μ₁, E₁, ν₁, and μ₂, E₂, ν₂ arerespective shear modulus in units of Pa, Young's modulus (elasticmodulus) in units of Pa, Poisson's ratio (unit less) of the glass-basedsubstrate and film materials, Γ_(c) ^(Glass) and Γ_(c) ^(IT) arecritical energy release rate of glass-based substrate and the interfacebetween substrate and film, respectively in units of J/m².

The common parameters to characterize the elastic mismatch between thefilm and the substrate are Dundurs' parameters α and β, as defined below

$\begin{matrix}{\alpha = \frac{{\overset{\_}{E}}_{1} - {\overset{\_}{E}}_{2}}{{\overset{\_}{E}}_{1} + {\overset{\_}{E}}_{2}}} & (1)\end{matrix}$where Ē=E/(1−ν²) for plain strain and

$\begin{matrix}{\beta = {\frac{1}{2}\frac{{\mu_{1}\left( {1 - {2v_{2}}} \right)} - {\mu_{2}\left( {1 - {2v_{1}}} \right)}}{{\mu_{1}\left( {1 - v_{2}} \right)} + {\mu_{2}\left( {1 - v_{1}} \right)}}}} & (2)\end{matrix}$

It is worth pointing out that the critical energy release rate isclosely related with the fracture toughness of the material through therelationship defined as

$\begin{matrix}{\Gamma = {\frac{1 - v^{2}}{E}K_{C}^{2}}} & (3)\end{matrix}$

Under the assumption that there is a pre-existing flaw in the film, upontensile loading the crack will extend vertically down as illustrated inFIG. 3. Right at the interface, the crack tends to deflect along theinterface if

$\begin{matrix}{\frac{G_{d}}{G_{p}} \geq \frac{\Gamma_{c}^{IT}}{\Gamma_{c}^{Glass}}} & (4)\end{matrix}$and the crack will penetrate into the glass-based substrate if

$\begin{matrix}{\frac{G_{dc}}{G_{pc}} < \frac{\Gamma^{IT}}{\Gamma^{Glass}}} & (5)\end{matrix}$where G_(d) and G_(p) and are the energy release rates of a deflectedcrack along the interface and a penetrated crack into the glass-basedsubstrate, respectively. On the left hand side of Equations (4) and (5),the ratio G_(d)/G_(p) is a strong function of elastic mismatch parameterα and weakly dependent on β; and on the right hand side, the toughnessratio Γ_(c) ^(IT)/Γ_(c) ^(Glass) is a material parameter.

FIG. 4 graphically illustrates the trend of G_(d)/G_(p) as a function ofelastic mismatch α, reproduced from a reference for doubly-deflectedcracks. (See Ming-Yuan, H. and J. W. Hutchinson, “Crack deflection at aninterface between dissimilar elastic materials,” International Journalof Solids and Structures, 1989, 25(9): pp. 1053-1067.)

It is evident that the ratio G_(d)/G_(p) is strongly dependent on α.Negative α means the film is stiffer than the glass-based substrate andpositive a means the film is softer than the glass-based substrate. Thetoughness ratio Γ_(c) ^(IT)/Γ_(c) ^(Glass), which is independent of α,is a horizontal line in FIG. 4. If the criterion in Equation (4) issatisfied, in FIG. 4, at the region above the horizontal line, the cracktends to deflect along the interface which may be beneficial for theretention of the average flexural strength of a substrate. On the otherhand, if the criterion in Equation (5) is satisfied, in FIG. 4, at theregion below the horizontal line, the crack tends to penetrate intoglass-based substrate which leads to degradation of the average flexuralstrength of the article, particularly those articles utilizingstrengthened or strong glass-based substrates as described elsewhereherein.

With regard to the above concept, an indium-tin-oxide (ITO) film (e.g.,as a hard film 110 comprising ITO) is utilized as an illustrativeexample according to the following analysis. For glass-based substrate,E₁=72 GPa, ν₁=0.22, and K_(1c)=0.7 MPa·m^(1/2); for ITO, E₂=99.8 GPa,and ν₂=0.25. (Zeng, K., et al., “Investigation of mechanical propertiesof transparent conducting oxide thin films.” Thin Solid Films, 2003,443(1-2): pp. 60-65.) The interfacial toughness between the ITO film andglass-based substrate can be approximately Γ_(in)=5 J/m², depending ondeposition conditions. (Cotterell, B. and Z. Chen, “Buckling andcracking of thin films on compliant substrates under compression,”International Journal of Fracture, 2000, 104(2): pp. 169-179.) This willgive the elastic mismatch α=−0.17 and Γ_(c) ^(IT)/Γ_(c) ^(Glass)=0.77.These values are plotted in FIG. 4. This fracture analysis predicts thatthe crack penetration into the glass-based substrate for the ITO filmwill be favored, which leads to degradation of the average flexuralstrength of the glass-based substrate, particularly a glass-basedsubstrate that is strengthened or strong. This is believed to be one ofthe potential underlying mechanisms observed with various hard films,including those films comprising indium-tin-oxide or other transparentconductive oxides, silicon nitride, and other hard films disposed onglass-based substrates, including strengthened or strong glass-basedsubstrates. As shown in FIG. 4, one way to mitigate the degradation ofthe average flexural strength can be to select appropriate materials tochange the elastic mismatch a (i.e., “Choice 1,” which involves shiftingthe elastic mismatch value a to the right) or to adjust the interfacialtoughness (i.e., “Choice 2,” which involves shifting the value of Gd/Gpdownward).

The theoretical analysis outlined above suggests that a crack mitigatingcomposite 130 a, 130 b, 130 c can be used to better retain the strengthof laminate articles 100 a, 100 b, 100 c, respectively. Specifically,the insertion of a crack mitigating composite 130 a, 130 b, 130 cbetween a glass-based substrate 120 and a hard film 110 makes crackmitigation, as defined herein, a more preferred path and thus thearticle is better able to retain its strength. In some embodiments, thecrack mitigating composite 130 a, 130 b, 130 c facilitates crackdeflection, as will be described in greater detail herein.

Glass-Based Substrate

Referring to FIGS. 1A-1C, the laminate articles 100 a, 100 b, 100 cinclude a glass-based substrate 120, which may be strengthened orstrong, as described herein, having opposing major surfaces 122, 124.Laminate article 100 a, 100 b, 100 c also includes a hard film 110disposed over at least one opposing major surface (122 or 124) of thesubstrate. In addition, laminate articles 100 a, 100 b, 100 c include acrack mitigating composite 130 a, 130 b, 130 c. With regard to articles100 a, 100 b, 100 c, the crack mitigating composite 130 a, 130 b, 130 cis disposed between the hard film 110 and the glass-based substrate 120.In one or more alternative embodiments, the crack mitigating composite130 a, 130 b, 130 c and/or the hard film 110 may be disposed on theminor surface(s) of the glass-based substrate 120 (e.g., an edge of thesubstrate that is perpendicular to the opposing major surfaces 122, 124)in addition to or instead of being disposed on at least one majorsurface (e.g., surfaces 122 or 124) or may be disposed on both majorsurfaces.

As used herein, the glass-based substrate 120 may be substantiallyplanar sheets, although other embodiments may utilize a curved orotherwise shaped or sculpted glass-based substrate. The glass-basedsubstrate 120 may be substantially clear, transparent and free fromlight scattering. The glass-based substrate may have a refractive indexin the range from about 1.45 to about 1.55. In one or more embodiments,the glass-based substrate 120 may be strengthened or characterized asstrong, as will be described in greater detail herein. The glass-basedsubstrate 120 may be relatively pristine and flaw-free (for example,having a low number of surface flaws or an average surface flaw sizeless than about 1 micron) before such strengthening. Where strengthenedor strong glass-based substrates 120 are utilized, such substrates maybe characterized as having a high average flexural strength (whencompared to glass-based substrates that are not strengthened or strong)or high surface strain-to-failure (when compared to glass-basedsubstrates that are not strengthened or strong) on one or more majoropposing surfaces of such substrates.

Additionally or alternatively, the thickness 12 of the glass-basedsubstrate 120 may vary along one or more of its dimensions for aestheticand/or functional reasons. For example, the edges of the glass-basedsubstrate 120 may be thicker as compared to more central regions of theglass-based substrate 120. The length, width and thickness dimensions ofthe glass-based substrate 120 may also vary according to the applicationor use of the article 100 a, 100 b, 100 c.

The glass-based substrate 120, according to one or more embodiments,includes an average flexural strength that may be measured before andafter the glass-based substrate 120 is combined with the hard film 110,crack mitigating composite 130 a, 130 b, 130 c and/or other films orlayers. In one or more embodiments described herein, the laminatearticles 100 a, 100 b, 100 c retain their average flexural strengthafter the combination of the glass-based substrate 120 with the hardfilm 110, crack mitigating composite 130 a, 130 b, 130 c and/or otherfilms, layers or materials, when compared to the average flexuralstrength of the glass-based substrate 120 before such a combination. Inother words, the average flexural strength of the articles 100 a, 100 b,100 c is substantially the same before and after the hard film 110,crack mitigating composite 130 a, 130 b, 130 c and/or other films orlayers are disposed on the glass-based substrate 120. In one or moreembodiments, the articles 100 a, 100 b, 100 c have an average flexuralstrength that is significantly greater than the average flexuralstrength of similar articles that do not include the crack mitigatingcomposite 130 a, 130 b, 130 c (e.g., a higher strength value than anarticle that comprises hard film 110 and glass-based substrate 120 indirect contact, without an intervening crack mitigating composite 130 a,130 b, 130 c). In other embodiments, the articles 100 a, 100 b, 100 chave an average flexural strength that is 50% or more of the averageflexural strength of similar articles comprising the glass-basedsubstrates alone (i.e., with no other coatings or films).

In accordance with one or more embodiments, the glass-based substrate120 has an average strain-to-failure that may be measured before andafter the glass-based substrate 120 is combined with the hard film 110,crack mitigating composite 130 a, 130 b, 130 c and/or other films orlayers. The term “average strain-to-failure” refers to the strain atwhich cracks propagate without application of additional load, typicallyleading to catastrophic failure in a given material, layer or film and,perhaps even bridge to another material, layer, or film, as describedherein. Average strain-to-failure may be measured using, for example,ball-on-ring testing. Without being bound by theory, the averagestrain-to-failure may be directly correlated to the average flexuralstrength using appropriate mathematical conversions. In specificembodiments, the glass-based substrate 120, which may be strengthened orstrong as described herein, has an average strain-to-failure that is0.5% or greater, 0.6% or greater, 0.7% or greater, 0.8% or greater, 0.9%or greater, 1% or greater, 1.1% or greater, 1.2% or greater, 1.3% orgreater, 1.4% or greater, 1.5% or greater or even 2% or greater, and allranges and sub-ranges between the foregoing values. Unless specifiedotherwise, the average strain-to-failure numbers supported herein weredetermined by Ring-on-ring testing. In specific embodiments, theglass-based substrate 120 has an average strain-to-failure of 1.2%,1.4%, 1.6%, 1.8%, 2.2%, 2.4%, 2.6%, 2.8% or 3% or greater, and allranges and sub-ranges between the foregoing values. The averagestrain-to-failure of the film 110 may be less than the averagestrain-to-failure of the glass-based substrate 120 and/or the averagestrain-to-failure of the crack mitigating composite 130 a-c. Withoutbeing bound by theory, it is believed that the average strain-to-failureof a glass-based substrate 120 or any other material is dependent on thesurface quality of such material. With respect to glass-basedsubstrates, e.g., substrates 120, the average strain-to-failure of aspecific glass-based substrate is dependent on the conditions of ionexchange or strengthening process utilized in addition to or instead ofthe surface quality of the glass-based substrate. In some embodiments,the glass-based substrate may have an elastic modulus from about 55 GPato about 100 GPa, and all ranges and sub-ranges between the foregoingvalues. In other embodiments, the glass-based substrate may have anelastic modulus from about 55 GPa to about 80 GPa. Further, otherimplementations employ glass-based substrates with an elastic modulusfrom 60 GPa to 90 GPa. The elastic modulus values of the glass-basedsubstrates recited in this disclosure were measured using ResonantUltrasound Spectroscopy.

In one or more embodiments, the glass-based substrate 120 retains itsaverage strain-to-failure after combination with the hard film 110,crack mitigating composite 130 a, 130 b, 130 c and/or other films orlayers. In other words, the average strain-to-failure of the glass-basedsubstrate 120 is substantially the same before and after the hard film110, crack mitigating composite 130 a-c and/or other films or layers aredisposed on the glass-based substrate 120. In one or more embodiments,the articles 100 a, 100 b, 100 c have an average strain-to-failure thatis significantly greater than the average strain-to-failure of similararticles that do not include the crack mitigating composite 130 a-c(e.g., a higher strain-to-failure than an article that comprises hardfilm 110 and glass-based substrate 120 in direct contact, without anintervening crack mitigating composite). For example, the articles 100a, 100 b, 100 c may exhibit average strain-to-failures that are 10% ormore higher, 25% higher, 50% higher, 100% higher, 200% higher or 300%higher, and all ranges and sub-ranges between the foregoing values, thanthe average strain-to-failure of similar articles that do not includethe crack mitigating composite 130 a, 130 b, 130 c. Similarly, thelaminate articles 100 a, 100 b, 100 c can be characterized by an averagestrain to failure of greater than about 0.5%, greater than about 0.8%,greater than about 1%, greater than about 1.2%, greater than about 1.4%,and all average strain to failure lower threshold values between theselevels.

The glass-based substrate 120 may be provided using a variety ofdifferent processes. For example, glass-based substrate forming methodsinclude float glass processes, press rolling processes, tube formingprocesses, updraw processes, and down-draw processes, for example,fusion draw and slot draw. In the float glass process, a glass-basedsubstrate that may be characterized by smooth surfaces and uniformthickness is made by floating molten glass on a bed of molten metal,typically tin. In an example process, molten glass that is fed onto thesurface of the molten tin bed forms a floating glass ribbon. As theglass ribbon flows along the tin bath, the temperature is graduallydecreased until the glass ribbon solidifies into a solid glass-basedsubstrate that can be lifted from the tin onto rollers. Once off thebath, the glass-based substrate can be cooled further and annealed toreduce internal stress.

Down-draw processes produce glass-based substrates having a uniformthickness that may possess relatively pristine surfaces. Because theaverage flexural strength of the glass-based substrate is controlled bythe frequency, amount and/or size of surface flaws, a pristine surfacethat has had minimal contact has a higher initial strength. When thishigh strength glass-based substrate is then further strengthened (e.g.,chemically or thermally), the resultant strength can be higher than thatof a glass-based substrate with a surface that has been lapped andpolished. Down-drawn glass-based substrates may be drawn to a thicknessof less than about 2 mm. In addition, down drawn glass-based substratesmay have a very flat, smooth surface that can be used in its finalapplication form, without the need for costly grinding and polishingprocesses.

The fusion draw process, for example, uses a drawing tank that has achannel for accepting molten raw material. The channel has weirs thatare open at the top along the length of the channel on both sides of thechannel. When the channel fills with molten material, the moltenmaterial overflows the weirs. Due to gravity, the molten material flowsdown the outside surfaces of the drawing tank as two flowing films.These outside surfaces of the drawing tank extend down and inwardly sothat they join at an edge below the drawing tank. The two flowing filmsjoin at this edge to fuse and form a single flowing substrate. Thefusion draw method offers the advantage that, because the two filmsflowing over the channel fuse together, neither of the outside surfacesof the resulting substrate comes in contact with any part of theapparatus. Thus, the surface properties of the fusion drawn substrateare not affected by such contact.

The slot draw process is distinct from the fusion draw method. In slotdraw processes, the molten raw material glass is provided to a drawingtank. The bottom of the drawing tank has an open slot with a nozzle thatextends the length of the slot. The molten material flows through theslot/nozzle and is drawn downward as a continuous substrate and into anannealing region.

Once formed, glass-based substrates 120 may be strengthened to formstrengthened glass-based substrates for use in the laminate articles 100a-c. As used herein, the term “strengthened glass-based substrate” mayrefer to a glass-based substrate that has been chemically strengthened,for example, through ion-exchange of larger ions for smaller ions in thesurface of the glass-based substrate. However, other strengtheningmethods known in the art, for example, thermal tempering, may beutilized to form strengthened glass-based substrates. As will bedescribed, strengthened glass-based substrates may include a glass-basedsubstrate having a surface compressive stress in its surface that aidsin the strength preservation of the glass-based substrate. As also usedherein, “strong” glass-based substrates are also within the scope ofthis disclosure and include glass-based substrates that may not haveundergone a specific strengthening process, and may not have a surfacecompressive stress, but are nevertheless strong as understood by thosewith ordinary skill in the art. Such strong glass-based substratearticles may be defined as glass sheet articles or glass-basedsubstrates having an average strain-to-failure greater than about 0.5%,0.7%, 1%, 1.5%, or even greater than 2%, and all ranges and sub-rangesbetween the foregoing values. These strong glass-based substrates can bemade, for example, by protecting the pristine glass surfaces aftermelting and forming the glass-based substrate. An example of suchprotection occurs in a fusion draw method, where the surfaces of theglass films do not come into contact with any part of the apparatus orother surface after forming. The glass-based substrates formed from afusion draw method derive their strength from their pristine surfacequality. A pristine surface quality can also be achieved through etchingor polishing and subsequent protection of glass-based substratesurfaces, and other methods known in the art. In one or moreembodiments, both strengthened glass-based substrates and the strongglass-based substrates may comprise glass sheet articles having anaverage strain-to-failure greater than about 0.5%, 0.7%, 1%, 1.5%, oreven greater than 2%, and all ranges and sub-ranges between theforegoing values, for example, when measured using ring-on-ring orball-on-ring flexural testing.

As mentioned above, the glass-based substrates described herein may bechemically strengthened by an ion exchange process to provide astrengthened glass-based substrate 120. The glass-based substrate mayalso be strengthened by other methods known in the art, for example,thermal tempering. In the ion-exchange process, typically by immersionof the glass-based substrate into a molten salt bath for a predeterminedperiod of time, ions at or near the surface(s) of the glass-basedsubstrate are exchanged for larger metal ions from the salt bath. Insome embodiments, the temperature of the molten salt bath is about 350°C. to 450° C. and the predetermined time period is about two to abouteight hours. The incorporation of the larger ions into the glass-basedsubstrate strengthens the glass-based substrate by creating acompressive stress in a near surface region or in regions at andadjacent to the surface(s) of the glass-based substrate. A correspondingtensile stress is induced within a central region or regions at adistance from the surface(s) of the glass-based substrate to balance thecompressive stress. Glass-based substrates utilizing this strengtheningprocess may be described more specifically as chemically-strengthenedglass-based substrates 120 or ion-exchanged glass-based substrates 120.Glass-based substrates 120 employed in the laminate articles 100 a-100 cthat are not strengthened may be referred to herein as non-strengthenedglass-based substrates.

In one example, sodium ions in a strengthened glass-based substrate 120are replaced by potassium ions from the molten salt bath, for example, apotassium nitrate salt bath, though other alkali metal ions havinglarger atomic radii, for example, rubidium or cesium, can replacesmaller alkali metal ions in the glass. According to particularembodiments, smaller alkali metal ions in the glass can be replaced byAg⁺ ions. Similarly, other alkali metal salts, for example, sulfates,phosphates, halides, and the like may be used in the ion exchangeprocess.

The replacement of smaller ions by larger ions at a temperature belowthat at which the glass network can relax produces a distribution ofions across the surface(s) of the strengthened glass-based substrate 120that results in a stress profile. The larger volume of the incoming ionproduces a compressive stress (CS) on the surface and tension (centraltension, or CT) in the center of the strengthened glass-based substrate120. Depth of exchange may be described as the depth within thestrengthened glass-based substrate 120 (i.e., the distance from asurface of the glass-based substrate to a central region of theglass-based substrate), at which ion exchange facilitated by the ionexchange process takes place.

Compressive stress (at the surface of the glass) is measured by surfacestress meter (FSM) using commercially available instruments such as theFSM-6000, manufactured by Orihara Industrial Co., Ltd. (Japan). Surfacestress measurements rely upon the accurate measurement of the stressoptical coefficient (SOC), which is related to the birefringence of theglass. SOC in turn is measured according to Procedure C (Glass DiscMethod) described in ASTM standard C770-16, entitled “Standard TestMethod for Measurement of Glass Stress-Optical Coefficient,” thecontents of which are incorporated herein by reference in theirentirety.

As used herein, depth of compression (DOC) means the depth at which thestress in the strengthened alkali aluminosilicate glass-based substratedescribed herein changes from compressive to tensile. When inducedchemically, the DOC may be measured by FSM or a scattered lightpolariscope (SCALP) depending on the ion exchange treatment. Where thestress in the glass article is generated by exchanging potassium ionsinto the glass article, FSM is used to measure DOC. Where the stress isgenerated by exchanging sodium ions into the glass article, SCALP isused to measure DOC. Where the stress in the glass article is generatedby exchanging both potassium and sodium ions into the glass, the DOC ismeasured by SCALP, since it is believed the exchange depth of sodiumindicates the DOC and the exchange depth of potassium ions indicates achange in the magnitude of the compressive stress (but not the change instress from compressive to tensile); the exchange depth of potassiumions in such glass articles is measured by FSM.

In some embodiments, a strengthened glass-based substrate 120 employedin the laminate articles 100 a-c can have a surface CS of 300 MPa orgreater, e.g., 400 MPa or greater, 450 MPa or greater, 500 MPa orgreater, 550 MPa or greater, 600 MPa or greater, 650 MPa or greater, 700MPa or greater, 750 MPa or greater or 800 MPa or greater, and all rangesand sub-ranges between the foregoing values. The strengthenedglass-based substrate 120 may have a DOC 15 μm or greater, 20 μm orgreater (e.g., 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm or greater)and/or a central tension of 10 MPa or greater, 20 MPa or greater, 30 MPaor greater, 40 MPa or greater (e.g., 42 MPa, 45 MPa, or 50 MPa orgreater) but less than 100 MPa (e.g., 95, 90, 85, 80, 75, 70, 65, 60, 55MPa or less), and all ranges and sub-ranges between the foregoingvalues. In one or more specific embodiments, the strengthenedglass-based substrate 120 has one or more of the following: a surface CSgreater than 500 MPa, a depth of compressive layer greater than 15 μm,and a central tension greater than 18 MPa.

Without being bound by theory, it is believed that strengthenedglass-based substrates 120 with a surface CS greater than 500 MPa and aDOC greater than about 15 μm typically have greater strain-to-failurethan non-strengthened glass-based substrates (or, in other words,glass-based substrates that have not been ion exchanged or otherwisestrengthened). In some aspects, the benefits of one or more embodimentsdescribed herein may not be as prominent with non-strengthened or weaklystrengthened types of glass-based substrates that do not meet theselevels of surface CS or DOC, because of the presence of handling orcommon glass surface damage events in many typical applications.However, as mentioned previously, in other specific applications wherethe glass-based substrate surfaces can be adequately protected fromscratches or surface damage (for example, by a protective coating orother layers), strong glass-based substrates with a relatively highstrain-to-failure can also be created through forming and protection ofa pristine glass surface quality, for example, by using the fusionforming method. In these alternate applications, the benefits of one ormore embodiments described herein can be similarly realized.

Example ion-exchangeable glasses that may be used in the strengthenedglass-based substrate 120 employed in the laminate articles 100 a-100 cmay include alkali aluminosilicate glass compositions or alkalialuminoborosilicate glass compositions, though other glass compositionsare contemplated. As used herein, “ion exchangeable” means that aglass-based substrate is capable of exchanging cations located at ornear the surface of the glass-based substrate with cations of the samevalence that are either larger or smaller in size. One example glasscomposition comprises SiO₂, B₂O₃ and Na₂O, where (SiO₂+B₂O₃)≥66 mol. %,and Na₂O≥9 mol. %. In some embodiments, the glass-based substrate 120includes a glass composition with 6 wt. % or more aluminum oxide. Insome embodiments, a glass-based substrate 120 includes a glasscomposition with one or more alkaline earth oxides, such that a contentof alkaline earth oxides is 5 wt. % or more. Suitable glasscompositions, in some embodiments, further comprise at least one of K₂O,MgO, and CaO. In some embodiments, the glass compositions used in theglass-based substrate 120 can comprise 61-75 mol. % SiO₂; 7-15 mol. %Al₂O₃; 0-12 mol. % B₂O₃; 9-21 mol. % Na₂O; 0-4 mol. % K₂O; 0-7 mol. %MgO; and 0-3 mol. % CaO.

A further example glass composition suitable for the glass-basedsubstrate 120, which may optionally be strengthened or strong,comprises: 60-70 mol. % SiO₂; 6-14 mol. % Al₂O₃; 0-15 mol. % B₂O₃; 0-15mol. % Li₂O; 0-20 mol. % Na₂O; 0-10 mol. % K₂O; 0-8 mol. % MgO; 0-10mol. % CaO; 0-5 mol. % ZrO₂; 0-1 mol. % SnO₂; 0-1 mol. % CeO₂; less than50 ppm As₂O₃; and less than 50 ppm Sb₂O₃; where 12 mol. %(Li₂O+Na₂O+K₂O)≤20 mol. % and 0 mol. %≤(MgO+CaO)≤10 mol. %.

A still further example glass composition suitable for the glass-basedsubstrate 120, which may optionally be strengthened or strong,comprises: 63.5-66.5 mol. % SiO₂; 8-12 mol. % Al₂O₃; 0-3 mol. % B₂O₃;0-5 mol. % Li₂O; 8-18 mol. % Na₂O; 0-5 mol. % K₂O; 1-7 mol. % MgO; 0-2.5mol. % CaO; 0-3 mol. % ZrO₂; 0.05-0.25 mol. % SnO₂; 0.05-0.5 mol. %CeO₂; less than 50 ppm As₂O₃; and less than 50 ppm Sb₂O₃; where 14 mol.% (Li₂O+Na₂O+K₂O)≤18 mol. % and 2 mol. %≤(MgO+CaO)≤7 mol. %.

In some embodiments, an alkali aluminosilicate glass compositionsuitable for the glass-based substrate 120, which may optionally bestrengthened or strong, comprises alumina, at least one alkali metaland, in some embodiments, greater than 50 mol. % SiO₂, in otherembodiments 58 mol. % or more SiO₂, and in still other embodiments 60mol. % or more SiO₂, all as further defined by the ratio given byEquation (6):

$\begin{matrix}{\frac{{{Al}_{2}O_{3}} + {B_{2}O_{3}}}{\sum{modifiers}} > 1} & (6)\end{matrix}$and the components are expressed in mol. % and the modifiers are alkalimetal oxides. This glass composition, in particular embodiments,comprises: 58-72 mol. % SiO₂; 9-17 mol. % Al₂O₃; 2-12 mol. % B₂O₃; 8-16mol. % Na₂O; 0-4 mol. % K₂O, and as further defined by Equation (6)above.

In some embodiments, the glass-based substrate 120, which may optionallybe strengthened or strong, may include an alkali aluminosilicate glasscomposition comprising: 64-68 mol. % SiO₂; 12-16 mol. % Na₂O; 8-12 mol.% Al₂O₃; 0-3 mol. % B₂O₃; 2-5 mol. % K₂O; 4-6 mol. % MgO; and 0-5 mol. %CaO, wherein: 66 mol. %≤SiO₂+B₂O₃+CaO≤69 mol. %;Na₂O+K₂O+B₂O₃+MgO+CaO+SrO>10 mol. %; 5 mol. %≤MgO+CaO+SrO≤8 mol. %;(Na₂O+B₂O₃)−Al₂O₃≤2 mol. %; 2 mol. %≤Na₂O−Al₂O₃≤6 mol. %; and 4 mol.%≤(Na₂O+K₂O)−Al₂O₃≤10 mol. %.

In some embodiments, the glass-based substrate 120, which may optionallybe strengthened or strong, may comprise an alkali silicate glasscomposition comprising: 2 mol % or more of Al₂O₃ and/or ZrO₂, or 4 mol %or more of Al₂O₃ and/or ZrO₂.

In some embodiments, the glass-based substrate used in the glass-basedsubstrate 120 of the laminate articles 100 a-100 c may be batched with0-2 mol % of at least one fining agent selected from a group thatincludes Na₂SO₄, NaCl, NaF, NaBr, K₂SO₄, KCl, KF, KBr, and SnO₂.

The glass-based substrate 120 according to one or more embodiments canhave a thickness 12 ranging from about 50 μm to 5 mm. Examplethicknesses 12 for the glass-based substrate 120 can range from 100 μmto 500 μm, e.g., 100, 200, 300, 400 or 500 μm. Further examplethicknesses 12 range from 500 μm to 1000 μm, e.g., 500, 600, 700, 800,900 or 1000 μm. The glass-based substrate 120 may have a thickness 12that is greater than 1 mm, e.g., about 2, 3, 4, or 5 mm. In one or moreembodiments, the glass-based substrate 120 may have a thickness 12 of 2mm or less, or less than 1 mm. The glass-based substrate 120 may be acidpolished or otherwise treated to remove or reduce the effect of surfaceflaws.

Hard Film

The laminate articles 100 a, 100 b, 100 c (see FIGS. 1A-1C) include ahard film 110 disposed on a surface of the glass-based substrate 120 andspecifically on the crack mitigating composite 130 a, 130 b, 130 c. Thehard film 110 may be disposed on one or both major surfaces 122, 124 ofthe glass-based substrate 120. In one or more embodiments, the film 110may be disposed on one or more minor surfaces (not shown) of theglass-based substrate 120 in addition to or instead of being disposed onone or both major surfaces 122, 124. In one or more embodiments, thehard film 110 is free of macroscopic scratches or defects that areeasily visible to the eye. Further, as shown in FIGS. 1A-1C, the film110 forms the effective interface 140 with the glass-based substrate120.

In one or more embodiments, the hard film 110 may lower the averageflexural strength of laminate articles 100 a, 100 b, 100 c (e.g., asincorporating such films and a glass-based substrate 120), through themechanisms described herein. In one or more embodiments, such mechanismsinclude instances in which the film 110 may lower the average flexuralstrength of the article because crack(s) that develop in the film 110bridge into the glass-based substrate 120. In other embodiments, themechanisms include instances in which the film may lower the averageflexural strength of the article because cracks developing in theglass-based substrates bridge into the film. The film 110 of one or moreembodiments may exhibit a strain-to-failure of 2% or less or astrain-to-failure that is less than the strain to failure of theglass-based substrates described herein. Further, the film 110 of one ormore embodiments may exhibit an elastic modulus that is greater than orequal to the elastic modulus of the glass-based substrate 120. Filmsincluding one or more of these attributes may be characterized withinthe disclosure as “brittle.”

In accordance with one or more embodiments of the laminate articles 100a-c, the hard film 110 may have a strain-to-failure (or crack onsetstrain level) that is lower than the strain-to-failure of theglass-based substrate 120. For example, the film 110 may have astrain-to-failure of about 2% or less, about 1.8% or less, about 1.6% orless, about 1.5% or less, about 1.4% or less, about 1.2% or less, about1% or less, about 0.8% or less, about 0.6% or less, about 0.5% or less,about 0.4% or less or about 0.2% or less, and all ranges and sub-rangesbetween the foregoing values. In some embodiments, the strain-to-failureof the film 110 may be lower than the strain-to-failure of thestrengthened glass-based substrates 120 that have a surface CS greaterthan 500 MPa and a DOC greater than about 15 μm. In one or moreembodiments, the film 110 may have a strain-to-failure that is 0.1% (ormore) lower or less, or in some cases, 0.5% (or more) lower or less, andall ranges and sub-ranges between the foregoing values, than thestrain-to-failure of the glass-based substrate 120. In one or moreembodiments, the film 110 may have a strain-to-failure that is about0.15% (or more), for example 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%,0.50%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95% or 1%,lower or less, and all ranges and sub-ranges between the foregoingvalues, than the strain-to-failure of the glass-based substrate 120.These strain-to-failure values can be measured, for example, usingball-on-ring and ring-on-ring flexural test methods combined withoptional microscopic or high-speed-camera analysis. Unless otherwisenoted, the strain-to-failure attributes and measurements of the films(e.g., films 110) on substrates (e.g., substrates 120) in the disclosurewere made by using a microscopic camera attached in situ to aring-on-ring flexural test setup (the same as for measuring COS asdescribed above) to measure displacement and other related data tocalculate the strain-to-failure value according to equations understoodby those with ordinary skill in the field of the disclosure. As alsounderstood by those with ordinary skill, these evaluations can beperformed during the application of load or stress, or in some cases byinspection after the application of load or stress. In cases in whichthe film, e.g., film 110, is electrically conductive, or a thinconductive layer is coated on the film, it is also understood by thosewith ordinary skill in the field that the onset of film cracking may bemeasured by analyzing the electrical resistivity of a conducting film.

Exemplary hard films 110 employed in the laminate articles 100 a-c mayhave an elastic modulus of 25 GPa or more and/or a hardness of 1.75 GPaor more, although some combinations outside of this range are possible.Generally, however, the hard films 110 employed in the laminate articles100 a-100 c are “hard” in the sense that they exhibit an elastic modulusof 25 GPa or more and/or a hardness of 1.75 GPa or more. In someembodiments the hard film 110 may have an elastic modulus of 50 GPa orgreater or even 70 GPa or greater, and all ranges and sub-ranges betweenthe foregoing values. For example, the film elastic modulus may be 55GPa, 60 GPa, 65 GPa, 75 GPa, 80 GPa, 85 GPa or more, and all ranges andsub-ranges between the foregoing values. In one or more embodiments, thefilm 110 may have a hardness value that is measured to be greater than3.0 GPa. For example, the film 110 may have a hardness of 5 GPa, 5.5GPa, 6 GPa, 6.5 GPa, 7 GPa, 7.5 GPa, 8 GPa, 8.5 GPa, 9 GPa, 9.5 GPa, 10GPa, 11 GPa, 12 GPa, 13 GPa, 14 GPa, 15 GPa, 16 GPa or greater, and allranges and sub-ranges between the foregoing values. According to anotherimplementation, the hard film 110 employed in the laminate articles 100a-c can exhibit a hardness of greater than or equal to 8 GPa, or greaterthan or equal to 12 GPa. These elastic modulus and hardness values canbe measured for such films 110 using known diamond nano-indentationmethods that are commonly used by those with ordinary skill in the fieldof the disclosure for determining the elastic modulus and hardness offilms. Exemplary diamond nano-indentation methods may utilize aBerkovich diamond indenter. Hardness and Young's modulus of thin filmcoatings, such as the films and layers of the disclosure (e.g., films110 and crack mitigating composites 130 a, 130 b, 130 c), are determinedusing widely accepted nanoindentation practices. (See Fischer-Cripps, A.C., “Critical Review of Analysis and Interpretation of NanoindentationTest Data,” Surface & Coatings Technology, 200, pp. 4153-4165, 2006(hereinafter “Fischer-Cripps”); and Hay, J. et al, “Continuous Stiffnessmeasurement During Instrumented Indentation Testing,” ExperimentalTechniques, 34 (3), pp. 86-94, 2010 (hereinafter “Hay”).) For coatings,it is typical to measure hardness and modulus as a function ofindentation depth. So long as the coating is of sufficient thickness, itis then possible to isolate the properties of the coating from theresulting response profiles. It should be recognized that if thecoatings are too thin (for example, less than ˜500 nm), it may not bepossible to completely isolate the coating properties as they can beinfluenced from the proximity of the substrate which may have differentmechanical properties. (See Hay.) The methods used to report theproperties herein are representative of the coatings themselves. Theprocess is to measure hardness and modulus versus indentation depth outto depths approaching 1000 nm. In the case of hard coatings on a softerglass, the response curves will reveal maximum levels of hardness andmodulus at relatively small indentation depths (≤about 200 nm). Atdeeper indentation depths both hardness and modulus will graduallydiminish as the response is influenced by the softer glass substrate. Inthis case, the coating hardness and modulus are taken be thoseassociated with the regions exhibiting the maximum hardness and modulus.In the case of soft coatings on a harder glass substrate, the coatingproperties will be indicated by the lowest hardness and modulus levelsthat occur at relatively small indentation depths. At deeper indentationdepths, the hardness and modulus will gradually increase due to theinfluence of the harder glass. These profiles of hardness and modulusversus depth can be obtained using the traditional Oliver and Pharrapproach (as described in Fischer-Cripps) or the more efficientcontinuous stiffness approach (see Hay). Extraction of reliablenanoindentation data requires that well-established protocols befollowed. Otherwise, these metrics can be subject to significant errors.These elastic modulus and hardness values are measured for such thinfilms using known diamond nano-indentation methods, as described above,with a Berkovich diamond indenter tip. Further, without being bound bytheory, the hardness values exhibited by the hard film 110 areindicative of the hardness of the laminate article 100 a-c, providedthat the hardness measurement made on the film is conducted with all ofthe aspects of the laminate article 100 a-c in place, including thecrack mitigating composite 130 a-c and the glass-based substrate 120.

The hard films 110 described herein employed in the laminate articles100 a-c may also exhibit a fracture toughness of less than about 10MPa·m^(1/2), or in some cases less than 5 MPa·m^(1/2), or in some casesless than 1 MPa·m^(1/2). For example, the film may have a fracturetoughness of 4.5 MPa·m^(1/2), 4 MPa·m^(1/2), 3.5 MPa·m^(1/2), 3MPa·m^(1/2), 2.5 MPa·m^(1/2), 2 MPa·m^(1/2), 1.5 MPa·m^(1/2), 1.4MPa·m^(1/2), 1.3 MPa·m^(1/2), 1.2 MPa·m^(1/2), 1.1 MPa·m^(1/2), 0.9MPa·m^(1/2), 0.8 MPa·m^(1/2), 0.7 MPa·m^(1/2), 0.6 MPa·m^(1/2), 0.5MPa·m^(1/2), 0.4 MPa·m^(1/2), 0.3 MPa·m^(1/2), 0.2 MPa·m^(1/2), 0.1MPa·m^(1/2) or less, and all ranges and sub-ranges between the foregoingvalues. Fracture toughness of thin films as reported herein was measuredas described in D. S Harding, W. C. Oliver, and G. M. Pharr, CrackingDuring Indentation and its use in the Measurement of Fracture Toughness,Mat. Res. Soc. Symp. Proc., vol. 356, 1995, 663-668.

The hard films 110 described herein employed in the laminate articles100 a-c may also have a critical strain energy release rate(G_(IC)=K_(IC) ²/E) that is less than about 0.1 kJ/m², or in some casesless than 0.01 kJ/m². In one or more embodiments, the film 110 may havea critical strain energy release rate of 0.09 kJ/m², 0.08 kJ/m², 0.07kJ/m², 0.06 kJ/m², 0.05 kJ/m², 0.04 kJ/m², 0.03 kJ/m², 0.02 kJ/m², 0.01kJ/m², 0.0075 kJ/m², 0.005 kJ/m², 0.0025 kJ/m² or less, and all rangesand sub-ranges between the foregoing values. Critical strain energyrelease rate is calculated using the values of fracture toughness andmodulus measured as described above.

In one or more embodiments, the hard film 110 may include a plurality oflayers, each with the same or with different thicknesses. In certainaspects, one or more layers within the film 110 may have a differentcomposition than the other layers in film 110. Various sequences oflayers making up film 110 are also contemplated by certain aspects ofthe disclosure. In one or more embodiments, each of the layers of thefilm may be characterized as brittle based on the influence of one ormore of the layers on the average flexural strength of the laminatearticle 100 a, 100 b, 100 c and/or the strain-to-failure, fracturetoughness, elastic modulus, or critical strain energy release ratevalues of the layer or layers, as otherwise described herein. In onevariant, the layers of the hard film 110 need not have identicalproperties, for example, elastic modulus and/or fracture toughness. Inanother variant, the layers of the film 110 may include differentmaterials from one another—e.g., as in alternating, thin layers havingdifferent compositions. In some embodiments, the hard film 110 includesan outermost layer or layers with high scratch resistance (e.g., asilicon nitride and/or a silicon dioxide layer or layers) and aninnermost layer or layers with other functional properties (e.g., aconducting film comprising a transparent conductive oxide, for example,ITO).

The compositions or material(s) of the hard film 110 can be limited, incertain embodiments, in the sense that the bulk of the film 110, or atleast its outermost layer or layers, should exhibit an appropriate levelof scratch resistance beneficial for the desired application of thelaminated article 100 a, 100 b, 100 c. According to some implementationsof the laminated articles 100 a, 100 b, 100 c, the hard film 110 cancomprise at least one of a metal-containing oxide, a metal-containingoxynitride, a metal-containing nitride, a metal-containing carbide, asilicon-containing polymer, a carbon, a semiconductor, and combinationsthereof. Some additional examples of the hard film 110 materials includeoxides, for example, SiO₂, Al₂O₃, TiO₂, Nb₂O₅, Ta₂O₅; oxynitrides, forexample, SiO_(x)N_(y), Si_(u)Al_(v)O_(x)N_(y), and AlO_(x)N_(y);nitrides, for example, SiN_(x), AlN_(x), cubic boron nitride, andTiN_(x); carbides, for example, SiC, TiC, and WC; combinations of theabove, for example, oxycarbides and oxy-carbo-nitrides (for example,SiC_(x)O_(y) and SiC_(x)O_(y)N_(z)); semiconductor materials, forexample, Si and Ge; transparent conductors, for example,indium-tin-oxide (ITO), tin oxide, fluorinated tin oxide, aluminum zincoxide, or zinc oxide; carbon nanotube or graphene-doped oxides; silveror other metal-doped oxides, highly siliceous polymers, for example,highly cured siloxanes and silsesquioxanes; diamond ordiamond-like-carbon materials; or selected metal films which can exhibita fracture behavior. Further, for those hard films 110 containing layeror layers with materials not typically associated with high scratchresistance (e.g., semiconductor materials, cubic boron nitride, etc.),the outermost layer or layers of the hard film can comprise ametal-containing oxide, a metal-containing oxynitride, ametal-containing nitride, a metal-containing carbide, asilicon-containing polymer, a diamond-like carbon material, andcombinations thereof. In addition, various multilayer hard coatingdesigns described in U.S. Pat. Nos. 9,079,802, 9,355,444, 9,359,261, and9,366,784, incorporated herein by reference, can also be employed in thelaminate articles and thereby obtain the benefit of the crack mitigatingcomposite schemes of the disclosure.

It is common to describe solids with “whole number formula”descriptions, such as Al₂O₃. It is also common to describe solids usingan equivalent “atomic fraction formula” description such asAl_(0.4)O_(0.6), which is equivalent to Al₂O₃. In the atomic fractionformula, the sum of all atoms in the formula is 0.4+0.6=1, and theatomic fractions of Al and O in the formula are 0.4 and 0.6respectively. Atomic fraction descriptions are described in many generaltextbooks and atomic fraction descriptions are often used to describealloys. See, for example: (i) Charles Kittel, Introduction to SolidState Physics, seventh edition, John Wiley & Sons, Inc., NY, 1996, pp.611-627; (ii) Smart and Moore, Solid State Chemistry, An introduction,Chapman & Hall University and Professional Division, London, 1992, pp.136-151; and (iii) James F. Shackelford, Introduction to MaterialsScience for Engineers, Sixth Edition, Pearson Prentice Hall, New Jersey,2005, pp. 404-418.

To speak generally about an alloy, such as aluminum oxide, withoutspecifying the particular subscript values, we can speak of Al_(v)O_(x).The description Al_(v)O_(x) can represent either Al₂O₃ orAl_(0.4)O_(0.6). If v+x were chosen to sum to 1 (i.e. v+x=1), then theformula would be an atomic fraction description. Similarly, morecomplicated mixtures can be described, such as Si_(u)Al_(y)O_(x)N_(y),where again, if the sum u+v+x+y were equal to 1, we would have theatomic fractions description case.

Atomic fraction formulas are sometimes easier to use in comparisons. Forinstance; an example alloy consisting of (Al₂O₃)_(0.3)(AlN)_(0.7) isclosely equivalent to the formula descriptionsAl_(0.448)O_(0.31)N_(0.241) and also Al₃₆₇O₂₅₄N₁₉₈. Another examplealloy consisting of (Al₂O₃)_(0.4)(AlN)_(0.6) is closely equivalent tothe formula descriptions Al_(0.438)O_(0.375)N_(0.188) and Al₃₇O₃₂N₁₆.The atomic fraction formulas Al_(0.448)O_(0.31)N_(0.241) andAl_(0.438)O_(0.375)N_(0.188) are relatively easy to compare to oneanother; For instance, we see that Al decreased in atomic fraction by0.01, O increased in atomic fraction by 0.065 and N decreased in atomicfraction by 0.053. It takes more detailed calculation and considerationto compare the whole number formula descriptions Al₃₆₇O₂₅₄N₁₉₈ andAl₃₇O₃₂N₁₆. Therefore, it is sometimes preferable to use atomic fractionformula descriptions of solids. Nonetheless, the use of Al_(v)O_(x)N_(y)is general since it captures any alloy containing Al, O and N atoms.

The hard film 110 can be disposed on the glass-based substrate 120 byvacuum deposition techniques, for example, chemical vapor deposition(e.g., plasma enhanced chemical vapor deposition, atmospheric pressurechemical vapor deposition, or plasma-enhanced atmospheric pressurechemical vapor deposition), physical vapor deposition (e.g., reactive ornonreactive sputtering or laser ablation), thermal, resistive, or e-beamevaporation, or atomic layer deposition. The hard film 110 may also bedisposed on one or more surfaces 122, 124 of the glass-based substrate120 using liquid-based techniques, for example, sol-gel coating orpolymer coating methods, for example spin, spray, slot draw, slide,wire-wound rod, blade/knife, air knife, curtain, gravure, and rollercoating among others. In some embodiments it may be desirable to useadhesion promoters, for example, silane-based materials, between thehard film 110 and the glass-based substrate 120, between the glass-basedsubstrate 120 and crack mitigating composite 130 a, 130 b, 130 c,between the layers (if any) of the crack mitigating composite 130 a, 130b, 130 c, between the layers (if any) of the film 110 and/or between thefilm 110 and the crack mitigating composite 130 a, 130 b, 130 c.

The thickness 11 of the hard film 110 (see FIGS. 1A-1C) can varydepending on the intended use of the laminate article 100 a, 100 b, 100c. In some embodiments the hard film 110, the thickness 11 may be in theranges from about 0.005 μm to about 5 μm, from about 0.2 μm to about 5μm, or from about 0.2 μm to about 0.5 μm. In some embodiments, thethickness 11 of the hard film 110 may range from about 0.005 μm to about10 μm, from about 0.05 μm to about 0.5 μm, from about 0.01 μm to about0.15 μm or from about 0.015 μm to about 0.2 μm, and all ranges andsub-ranges between the foregoing values.

In some embodiments of the laminate articles 100 a, 100 b, 100 c, it maybe advantageous to include a material (or materials) in the hard film110 (e.g., as comprising a single layer, dual-layer or multi-layerstructure) that has: (1) a refractive index that is similar to (orgreater than) the refractive index of either the glass-based substrate120, the crack mitigating composite 130 a, 130 b, 130 c and/or otherfilms or layers in order to minimize optical interference effects; (2) arefractive index (real and/or imaginary components) that is tuned toachieve anti-reflective interference effects; and/or (3) a refractiveindex (real and/or imaginary components) that is tuned to achievewavelength-selective reflective or wavelength-selective absorptiveeffects, for example, to achieve UV or IR blocking or reflection, or toachieve coloring/tinting effects. In some implementations of thelaminate articles 100 a-c, for example, the hard film 110 can comprise amulti-layer antireflection coating, in which the crack mitigatingcomposite 130 a-c and the hard film 110 collectively comprise a photopicaverage single-side reflectance of less than about 2%. As referenced inthis disclosure, a single-side reflectance value is measured byoptically coupling the rear surface of the glass-based substrate to astrong light absorber, effectively removing the reflection from the backsurface of the substrate from the measurement. Further, a photopicaverage is obtained by weighting the measured reflectance according tothe sensitivity of the human eye, and averaging the result, usingmethods readily understood by those with ordinary skill in the field.

In one or more embodiments, the hard film 110 may have a refractiveindex that is greater than the refractive index of the glass-basedsubstrate 120 and/or greater than the refractive index of the crackmitigating composite 130 a, 130 b, 130 c. In one or more embodiments,the film 110 may have a refractive index in the range from about 1.7 toabout 2.2, or in the range from about 1.4 to about 1.6, or in the rangefrom about 1.6 to about 1.9, and all ranges and sub-ranges between theforegoing values. Some embodiments can employ a film 110 having one ormore layers in which such layer(s) have a refractive index comparable tothat of the substrate, even if the aggregate refractive index of thefilm exceeds that of the substrate (e.g., a film 110 with one or moresilica layers and a balance of silicon nitride layer(s) disposed over asubstrate 120 having a silicate glass composition).

The hard film 110 may also serve multiple functions, including scratchresistance, or be integrated with additional film(s) or layers asdescribed herein that serve other functions than the scratch-resistanceassociated with the hard film 110. For example, the hard film 110 mayinclude UV or IR light reflecting or absorbing layers, anti-reflectionlayers, anti-glare layers, dirt-resistant layers, self-cleaning layers,scratch-resistant layers, barrier layers, passivation layers, hermeticlayers, diffusion-blocking layers, fingerprint-resistant layers, and thelike. Further, the film 110 may include conducting or semi-conductinglayers, thin film transistor layers, EMI shielding layers, breakagesensors, alarm sensors, electrochromic materials, photochromicmaterials, touch sensing layers, or information display layers. The film110 and/or any of the foregoing layers may include colorants or tint.When information display layers are integrated into the laminate article100 a, 100 b, 100 c, the article may form part of a touch-sensitivedisplay, a transparent display, or a heads-up display. In such cases, itmay be desirable that the hard film 110 performs an interferencefunction, which selectively transmits, reflects, or absorbs differentwavelengths or colors of light. For example, the hard film 110 mayselectively reflect a targeted wavelength in a heads-up displayapplication.

Other functional properties of the hard film 110 besides scratchresistance include optical properties, electrical properties and/ormechanical properties, for example, hardness, elastic modulus,strain-to-failure, abrasion resistance, mechanical durability,coefficient of friction, electrical conductivity, electricalresistivity, electron mobility, electron or hole carrier doping, opticalrefractive index, density, opacity, transparency, reflectivity,absorptivity, transmissivity and the like. These functional propertiesare substantially maintained or even improved after the hard film 110 iscombined with the glass-based substrate 120, crack mitigating composite130 a, 130 b, 130 c and/or other films included in the laminate article100 a, 100 b, 100 c.

Crack Mitigating Composite

As described herein, the crack mitigating composite 130 a, 130 b, 130 c(see FIGS. 1A-1C) suppresses crack growth through the effectiveinterface 140 in laminate articles 100 a, 100 b, 100 c. The crackmitigating composite 130 a-c may suppress crack growth by one or more ofthe following mechanisms: 1) reduction of stress intensity at crack tipsdue to changing elastic modulus within the composite structure; 2) crackblunting through plastic deformation within the composite structure; and3) crack deflection by providing a preferred path for crack growth whichis tortuous and consumes fracture energy within the crack mitigatingcomposite/stack instead of within the hard film 110 or glass-basedsubstrate 120.

With regard to the laminate article 100 a-c, the crack mitigatingcomposite 130 a-c comprises an inorganic element 33 and a polymericelement 35. In these aspects, the crack mitigating composite 130 a-cincludes an inorganic element 33 and a polymeric element 35, either orboth in the form of one or more layers, films, or other structures, suchas particulate, fibers and/or whiskers. In some embodiments, theinorganic element 33 can comprise an oxide, a nitride, or an oxynitride;and the polymeric element 35 can comprise at least one of a polyimide, apolycarbonate, a polyurethane, a polyester and a fluorinated polymer. Insome implementations, the inorganic element 33 can comprise one or moreof SiO₂, Al₂O₃, ZrO₂, CaO, CaCO₃, SnO, ZnO, SiN_(x), AlN_(x),AlO_(x)N_(y) or SiO_(x)N_(y); and/or the polymeric element 35 of thecrack mitigating composite 130 a-c can comprise a polyimide derived fromor otherwise comprising one or more of poly(pyromelliticdianhydride-co-4,4′-oxydianiline) (PMDA-ODA); 4,4′-oxidiphthalicanhydride and 4,4′-diaminodiphenyl ether monomers (ODPA-ODA;biphenyltetracarboxylicdianhydride-4,40-oxydianiline (BPDA-ODA); and afluorinated polyimide. In some cases, the polymer component or theentire composite can demonstrate a high temperature tolerance, which canbe characterized in multiple ways including one or more of thefollowing: 1) a 2% or lower change in mass of the layer or completecrack mitigating composite; and 2) a 2% or lower change in opticalreflectance or transmittance upon heating the article to 200° C. for 30minutes, or, in some cases, 250° C. for 30 minutes.

According to some embodiments of the laminate articles 100 a-c, thecrack mitigating composite 130 a-c includes an inorganic element 33 anda polymeric element 35, with greater than about 20% by volume ofmaterial associated with the inorganic element 33 and greater than about0.5% or more by volume of material associated with the polymeric element35. For example, the amount of material associated with the inorganicelement 35 can be greater than about 20%, 30%, 40%, 50%, 60% by volume,and all amounts between these volumetric levels. Preferably, thepolymeric element 35 comprises polymeric material having C—C, C—N, C—Oand/or C═C bonds as polymeric chain-forming bonds. Further, in someembodiments, the crack mitigating composite 130 a-c can have a compositecrack-onset-strain (COS) value of greater than about 0.8%, greater than1%, greater than about 1.5%, and all COS values between or above theselevels. Further, the crack mitigating composite 130 a-c, inclusive ofits inorganic and polymer elements 33, 35, may be characterized by anelastic modulus of greater than 30 GPa. For example, the crackmitigating composite 130 a-c can be characterized by an elastic modulusof 30.5 GPa, 31 GPa, 32 GPa, 33 GPa, 34 GPa, 35 GPa, 40 GPa, 45 GPa, 50GPa, and so on, including all elastic modulus values between theselevels, and conceivably up to 80 GPa and even approaching 120 GPa insome cases.

Further, in some embodiments of the laminate article 100 a-c, the crackmitigating composite 130 a-c can be characterized by an elastic modulusratio between the inorganic element 33 and the polymeric element 35 ofgreater than 10:1 (e.g., an inorganic element 33 with an elastic modulusof 150 GPa and a polymeric element with an elastic modulus of 10 GPawould result in an elastic modulus ratio of 15:1). For example, theelastic modulus ratio of the crack mitigating composite 130 a can be11:1, 12:1, 13:1, 14:1, 15:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1,90:1, 100:1 and all elastic modulus ratios between or above theseratios. According to some embodiments, a practical elastic modulus ratiolimit for the crack mitigating composite 130 a-c is about 500:1 forcertain very low elastic modulus polymeric elements 35 (e.g., <1 GPa)coupled with relatively high elastic modulus inorganic elements 33(e.g., >75 GPa) incorporated within the crack mitigating composite 130a-c.

Further, as shown in FIGS. 1B-1C, the crack mitigating composite 130 b,130 c of the laminate articles 100 b, 100 c can include an inorganicelement 33 in the form of one or more layers, and a polymeric element 35in the form of one or more layers. Without being bound by theory, theretained strength, optical properties and scratch resistance values ofthe laminate articles 100 b-c can be obtained for various quantities,combinations, thicknesses and/or compositions of the layer or layersthat make up each of the inorganic element 33 and the polymeric element35. Preferably, the laminate articles (e.g., laminate articles 100 b,100 c) employing the inorganic and polymeric elements 33, 35 in the formof one or more layers each do so such that the layers of the inorganicand polymeric elements 33, 35 are alternating. In some embodiments, thelaminate article 100 b, 100 c includes a crack mitigating composite 130b, 130 c such that a layer of the inorganic element 33 is in contactwith at least one of the glass-based substrate 120 and the hard film110. In the scenario in which a layer of the inorganic element 33 is incontact with both of the glass-based substrate 120 and the hard-film110, different layers of the inorganic element 33 will serve thisfunction as at least one layer of the polymeric element 35 will beinterposed between these layers.

As described herein and noted earlier, the “elastic modulus” or “averageelastic modulus” of the crack mitigating composite 130 b, 130 c,inclusive of its inorganic and polymer elements 33, 35 in the form oflayers, can be calculated by taking the measured values of each layer ofthe inorganic and polymeric elements 33, 35, as measured on a singlefilm basis on the order of 100 nm to 1000 nm in thickness and thencalculating a volumetric average elastic modulus for the crackmitigating composite 130 b. In addition, the volumetric average elasticmodulus can be calculated as understood by those with ordinary skill inthe field of the disclosure, e.g., in view of volumetric estimates oractual volumetric measurements for each of the layers of the inorganicand polymeric elements 33, 35. Further, these methods of calculating anaverage elastic modulus of the crack mitigating composite agree closelywith measurements of elastic modulus made directly on the crackmitigating composite through nanoindentation methods, as also describedin the disclosure.

As shown in FIGS. 1B and 1C, the crack mitigating composite 130 b, 130 cof the laminated article 100 b, 100 c includes an inorganic element 33with one or more layers having a thickness 63. In some aspects, thethickness 63 of each layer of the inorganic element 33 can range fromabout 1 nm to about 200 nm, preferably from about 5 nm to about 150 nm.Further, in some aspects, the thickness 65 of each layer of thepolymeric element 35 can range from about 1 nm to about 500 nm,preferably from about 5 nm to about 300 nm. According to anotherimplementation, the total thickness 13 b of the crack mitigatingcomposite 130 b can range from about 10 nm to about 1000 nm. In anotheraspect, the total thickness 13 b of the crack mitigating composite 130 branges from about 50 nm to about 750 nm. In additional embodiments, thetotal thickness 13 b of the crack mitigating composite 130 b ranges fromabout 25 nm to about 1000 nm, from about 50 nm to about 800 nm, fromabout 50 nm to about 700 nm, from about 50 nm to about 600 nm, fromabout 50 nm to about 500 nm, and all ranges and sub-ranges of totalthicknesses within these ranges.

In some implementations, the laminate article 100 b, 100 c can include acrack mitigating composite 130 b, 130 c governed by a thickness ratiofor the layers of its inorganic and polymeric elements 33, 35. Forexample, a ratio the total thickness of the polymeric element 35 (i.e.,the sum of the thickness 65 values for each of its layers) and theinorganic element 33 (i.e., the sum of the thickness 63 values for eachof its layers) can be from about 0.1:1 to about 5:1. In otherimplementations, the thickness ratio can be about 0.2:1 to about 3:1. Asalso understood herein, the implementations of the laminate article 100b, 100 c and crack mitigating composite 130 b, 130 c governed by suchthickness ratios are configured such that the thickness ratios arecalculated independent of any additional layers added to the crackmitigating composite 130 b, 130 c immediately adjacent to one or both ofthe hard film 110 and/or glass-based substrate 120. Such layers, asdescribed herein, are referred to as “tie layers” and are typically onehalf to an order (or orders) of magnitude thinner than the other layersof the inorganic and polymeric elements 33, 35.

According to other embodiments of the laminate articles 100 b, 100 c,the crack mitigating composite 130 b, 130 c includes a hardnesssufficient to retain the scratch resistance of the hard film 110, whilealso exhibiting a toughness sufficient to improve or otherwise retainthe flexural strength of the glass-based substrate 120 and a hard film110. To find a beneficial balance between hardness and toughness, theelastic modulus, E, and the hardness, H, of the crack mitigatingcomposite 130 b, 130 c can be tailored by controlling the thicknessratio between the thickness of the layers of the polymeric element 35(e.g., the sum of the thicknesses 63) and the total thickness 13 b, 13 cof the composite. As shown in FIGS. 6A and 6B, a plots of elasticmodulus (GPa) and hardness (GPa) of a crack mitigating composite, asdisposed on a glass-based substrate, as a function of the ratio of thethickness of the polymeric layer in the composite to the thickness ofthe complete crack mitigating composite, as measured according to ananoindentation method, according to some embodiments of the disclosure.As is evident from FIGS. 6A & 6B, increases in the thickness ratio ofthe total thickness of the polymeric element to the total thickness ofthe crack mitigating composite (i.e., about 400 nm for the data points)tend to result in decreased elastic modulus and hardness levels for thelaminate articles. In addition, the fitted lines to the data depicted inFIGS. 6A and 6B have R² values of 0.93 and 0.91, respectively,indicating a strong correlation between thickness ratio and elasticmodulus or hardness of the crack mitigating composite.

Referring now more generally to laminate articles 100 a-c, theinterfacial properties at an effective interface 140 between the hardfilm 110 and the crack mitigating composite 130 a-c, or between thecrack mitigating composite 130 a-c and the substrate 120, are modified,generally by virtue of the crack mitigating composite 130 a-c, such thatthe article 100 a-c substantially retains its average flexural strength,and the hard film 110 retains functional properties for its application,particularly scratch-resistance. For example, in some embodiments of thelaminate article 100 a-c, the article is characterized by an averageflexural strength that is greater than or equal to about 50% of anaverage flexural strength of the glass-substrate (i.e., as testedwithout a crack mitigating composite 130 a-c and hard film 110structures disposed thereon).

In one or more embodiments of the laminated articles 100 a-c depicted inFIGS. 1A-1C, the crack mitigating composite 130 a-c may form a preferredpath of crack propagation other than bridging between the hard film 110and the glass-based substrate 120. In other words, the crack mitigatingcomposite 130 a-c may deflect a crack, forming in one of the film 110and the glass-based substrate 120 and propagating toward the other ofthe film 110 and the glass-based substrate 120, into the crackmitigating composite 130 a-c. In such embodiments, the crack maypropagate through the crack mitigating composite 130 a-c in a directionsubstantially parallel to at least one of the first interface 150 or thesecond interface 160 for laminate articles 100 a-c. As depicted in FIG.5A, the crack becomes a cohesive failure 180, when confined within thecrack mitigating composite 130 a-c. As used herein, the term “cohesivefailure” relates to crack propagation substantially confined within thecrack mitigating composite 130 a-c.

The crack mitigating composite 130 a-c, when configured to develop acohesive failure 180 as shown in FIG. 5A, provides a preferred path forcrack propagation in such embodiments. The crack mitigating composite130 a-c may cause a crack originating in the hard film 110 or theglass-based substrate 120 and entering into the crack mitigatingcomposite 130 a-c to remain in the crack mitigating composite.Alternatively, or additionally, the crack mitigating composite 130 a-cof laminate articles 100 a-c effectively confines a crack originating inone of the hard film 110 and glass-based substrate 120 from propagatinginto the other of such film and glass-based substrate. Similarly, thecrack mitigating composite 130 a-c of laminate article 100 a-ceffectively confines a crack originating in one of the composite 130 a-cand glass-based substrate 120 from propagating into the other suchcomposite and substrate. These behaviors may be characterizedindividually or collectively as crack deflection. In this way, the crackis deflected from bridging between the film 110 and the glass-basedsubstrate 120, or between the crack mitigating composite 130 a-c and theglass-based substrate 120. In one or more embodiments, the crackmitigating composite 130 a-c may provide a low toughness layer orinterface that exhibits a low fracture toughness and/or a low criticalstrain energy release rate, which may promote crack deflection into thecrack mitigating composite 130 a-c instead of through the crackmitigating composite into the film 110 and/or glass-based substrate 120.As used herein, “facilitate” includes creating favorable conditions inwhich the crack deflects into the crack mitigating composite 130 a-cinstead of propagating into the glass-based substrate 120 or the film110. The term “facilitate” may also include creating a less tortuouspath for crack propagation into and/or through the crack mitigatingcomposite 130 a-c instead of into the glass-based substrate 120 or thefilm 110.

In accordance with one or more embodiments of the laminate article 100a-c, the crack mitigating composite 130 a-c may have an averagestrain-to-failure that is greater than the average strain-to-failure ofthe hard film 110. In one or more embodiments of laminate articles 100a-c, the crack mitigating composite 130 a-c may have an averagestrain-to-failure that is equal to or greater than about 0.5%, 0.7%, 1%,1.5%, 2%, or even 4%. The crack mitigating composite 130 a-c may have anaverage strain-to-failure of 0.6%, 0.8%, 0.9%, 1.1%, 1.2%, 1.3%, 1.4%,1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0% 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%,3.4%, 3.6%, 3.8%, 4%, 5% or 6% or greater, and all ranges and sub-rangesbetween the foregoing values. In one or more embodiments, the hard film110 may have an average strain-to-failure (crack onset strain) that is1.5%, 1.0%, 0.7%, 0.5%, or even 0.4% or less, and all ranges andsub-ranges between the foregoing values. The film 110 may have anaverage strain-to-failure of 1.4%, 1.3%, 1.2%, 1.1%, 0.9%, 0.8%, 0.6%,0.3%, 0.2%, 0.1% or less, and all ranges and sub-ranges between theforegoing values. The average strain-to-failure of the glass-basedsubstrate 120 may be greater than the average strain-to-failure of thehard film 110 for laminate articles 100 a-c, and in some instances, maybe greater than the average strain-to-failure of the crack mitigatingcomposite 130 a-c. In some other specific embodiments of laminatedarticles 100 a-c, the crack mitigating composite 130 a-c may have ahigher average strain-to-failure than the glass-based substrate 120, tominimize any negative mechanical effect of the crack mitigatingcomposite on the glass-based substrate.

The crack mitigating composite 130 a-c, according to one or moreembodiments, may have a critical strain energy release rate(G_(IC)=K_(IC) ²/E) that is greater than the critical strain energyrelease rate of the hard film 110. In other examples, the crackmitigating composite 130 a-c may exhibit a critical strain energyrelease rate that is less than 0.25 times, or less than 0.5 times, thecritical strain energy release rate of the glass-based substrate. Inspecific embodiments, the critical strain energy release rate of thecrack mitigating composite 130 a-c can be about 0.1 kJ/m² or less, about0.09 kJ/m² or less, about 0.08 kJ/m² or less, about 0.07 kJ/m² or less,about 0.06 kJ/m² or less, about 0.05 kJ/m² or less, about 0.04 kJ/m² orless, about 0.03 kJ/m² or less, about 0.02 kJ/m² or less, about 0.01kJ/m² or less, about 0.005 kJ/m² or less, about 0.003 kJ/m² or less,about 0.002 kJ/m² or less, about 0.001 kJ/m² or less; but in someembodiments, greater than about 0.0001 kJ/m² (i.e., greater than about0.1 J/m²), and all ranges and sub-ranges between the foregoing values.

The crack mitigating composite 130 a-c employed in laminate articles 100a-c may have a refractive index that is greater than the refractiveindex of the glass-based substrate 120. In one or more embodiments, therefractive index of the crack mitigating composite 130 a-c may be lessthan the refractive index of the hard film 110. In some embodiments, therefractive index of the crack mitigating composite 130 a-c may bebetween the refractive index of the glass-based substrate 120 and thefilm 110. For example, the refractive index of the crack mitigatingcomposite 130 a-c may be in the range from about 1.45 to about 1.95,from about 1.5 to about 1.8, or from about 1.6 to about 1.75, and allranges and sub-ranges between the foregoing values. Alternatively, thecrack mitigating composite 130 a-c may have a refractive index that issubstantially the same as the glass-based substrate, or a refractiveindex that is not more than 0.05 index units greater than or less thanthat of the glass-based substrate over a substantial portion of thevisible wavelength range (e.g. from 450 to 650 nm). In certainimplementations, the crack mitigating composite 130 a-c is configuredsuch that the optical transmittance of the substrate and the crackmitigating composite vary by 1% or less from the optical transmittanceof the substrate alone. Put another way, the crack mitigating composite130 a-c can be configured such that the optical properties (e.g.,optical transmittance and reflectance) of the substrate are retained.

In one or more embodiments, the crack mitigating composite 130 a-c ofthe laminate articles 100 a, 100 b, 100 c is able to withstand hightemperature processes. Such processes can include vacuum depositionprocesses, for example, chemical vapor deposition (e.g., plasma-enhancedchemical vapor deposition), physical vapor deposition (e.g., reactive ornonreactive sputtering or laser ablation), thermal or e-beam evaporationand/or atomic layer deposition. In one or more specific embodiments, thecrack mitigating composite 130 a-c is able to withstand a vacuumdeposition process in which the hard film 110 and/or other filmsdisposed on the glass-based substrate 120 are deposited on the crackmitigating composite 130 a-c via vacuum deposition. As used herein, theterm “withstand” includes the resistance of the crack mitigatingcomposite 130 a-c to temperatures exceeding 100° C., 200° C., 300° C.,400° C., 500° C., 600° C. and potentially even greater temperatures suchthat no more than 10% weight loss and/or no more than 2% loss in opticaltransmittance is observed in the crack mitigating composite. In someembodiments, the crack mitigating composite 130 a-c may be considered towithstand the vacuum deposition or temperature treatment process if thecrack mitigating composite 130 a-c experiences a weight loss of 10% orless, 8% or less, 6% or less, 4% or less, 2% or less or 1% or less, andall ranges and sub-ranges between the foregoing values, after depositionof the film 110 and/or other films on the glass-based substrate (and onthe crack mitigating composite 130 a-c). The deposition process (ortesting after the deposition process) under which the crack mitigatingcomposite 130 a-c experiences weight loss can include temperatures ofabout 100° C. or greater, 200° C. or greater, 300° C. or greater, 400°C. or greater; environments that are rich in a specific gas (e.g.,oxygen, nitrogen, argon etc.); and/or environments in which depositionmay be performed under high vacuum (e.g. 10⁻⁶ Torr), under atmosphericconditions and/or at pressures therebetween (e.g., 10 mTorr). As will bediscussed herein, the material utilized to form the crack mitigatingcomposite 130 a or stack 130 b may be specifically selected for its hightemperature tolerance (i.e., the ability to withstand high temperatureprocesses, for example, vacuum deposition processes) and/or itsenvironmental tolerance (i.e., the ability to withstand environmentsrich in a specific gas or at a specific pressure). These tolerances mayinclude high temperature tolerance, high vacuum tolerance, low vacuumoutgassing, a high tolerance to plasma or ionized gases, a hightolerance to ozone, a high tolerance to UV, a high tolerance tosolvents, or a high tolerance to acids or bases. In some instances, thecrack mitigating composite 130 a-c may be selected to pass an outgassingtest according to ASTM E595.

With regard to processing of the crack mitigating composite 130 a-c,various processes can be used to deposit, coat, or otherwise form itsinorganic and polymeric elements 33, 35. For example, wet-coatingmethods, e.g., spin-casting, spray, and dip-coating, can be employedwith various organic solvents, at least for development of the polymericelement 35. Preferably, however, various vacuum-based depositionmethods, e.g., thermal evaporation, e-beam evaporation, sputtering, andCVD methods, can be employed to fabricate both of the inorganic andpolymeric elements 33, 35. Vacuum deposition methods are advantageous inthat they do not rely on the use of any organic solvents, which can betoxic. Further, vacuum deposition methods, relative to other depositionand forming methods, can achieve better control of the thickness, layeruniformity and adhesion between the layers of the crack mitigatingcomposite 130 a-c, and between the layers of the composite and the hardfilm 110 or glass-based substrate 120.

For example, these processing techniques can be demonstrated by thescanning electron microscope (SEM) image in FIG. 7 from a cross-sectionof a laminate article comprising a glass-based substrate 720, a hardfilm 710 and a crack mitigating composite 730 comprising two inorganiclayers 733 and two polymeric layers 735 according to some embodiments ofthis disclosure. In the laminate article depicted in FIG. 7, an organiclayer (PMDA-ODA) 735 is co-evaporated by thermal evaporation and aninorganic layer 733, Al₂O₃, is deposited by e-beam evaporation on aglass-based substrate 720. These steps were repeated to complete thecrack mitigating composite 730, which comprises two layers of polyimideand two layers of Al₂O₃. Further, PMDA and ODA are polyimide precursors(e.g., of the polymeric layer 735), which undergo step polymerizationwhen deposited onto the surface of the glass-based substrate 720 or asubsequent layer of the inorganic layer 733, and are then thermallycured at 200° C. to complete the formation of the polyimide layer. Usingthese vacuum-based deposition processes, e.g., as depicted in the FIG. 7image of a laminate article produced according to the foregoing, both ofthe inorganic and polymeric layers 733, 735 of the crack mitigatingcomposite 730 can be deposited in a single chamber that is capable ofintroducing multiple precursor sources. In a preferred embodiment,additional ion cleaning steps are conducted between the deposition ofeach of the layers making up the inorganic and polymeric layers 733, 735to improve adhesion with subsequent layers and/or the hard film 710. Inaddition, some aspects of the crack mitigating composites 130 a-c of thelaminate articles 100 a-100 c, including the article depicted in FIG. 7,are fabricated according to the foregoing, followed by deposition of ahard film 110 comprising a silicon nitride (SiN_(x)) with aplasma-enhanced chemical vapor deposition technique. The SiNxscratch-resistant film (e.g., film 710 as shown in FIG. 7) was depositedin a Plasma-Therm high density plasma-enhanced vapor deposition (HDPCVD)Versaline system at 200° C. with a silane precursor gas and nitrogengas.

Further, the crack mitigating composite 130 a-c of one or moreembodiments of the laminate articles 100 a-c (see FIGS. 1A-1C) mayexhibit higher temperature tolerance, robustness to UV ozone or plasmatreatments, UV transparency, robustness to environmental aging, lowoutgassing in vacuum environments, and the like. In instances where thehard film 110 is also formed by vacuum deposition, both the crackmitigating composite 130 a-c and the film 110 can be formed in the sameor similar vacuum deposition chamber or using the same or similarcoating equipment.

According to some embodiments, the hard film 110 of the laminate article100 a-c, which comprises a crack mitigating composite 130 a-c, ischaracterized by no peeling or substantially no peeling from the articleupon exposure of the film 110 to a Garnet scratch test. As used herein,the “Garnet scratch test” is performed by attaching a ˜6 mm diametercircular piece of 150 grit garnet sandpaper to the head of a TaberAbraser unit using a double-sided adhesive tape. A total of 1 kg load isapplied to the abrasive head (˜650 g added load plus ˜350 g spindleload). Alternately, a total of 4 kg load may be applied. The abrasivehead is then swept in a single scratching pass of ˜30 mm length over thesurface of the sample, which is then inspected for scratches. Althoughsome scratches or damage marks may be visible on the sample, thecriteria of “substantially no peeling,” as used herein, is defined ashaving no visible regions in the center of the ˜30 mm Garnet scratchpath larger than about 100 microns in any spatial dimension where thescratch resistant film 110 is completely removed from the substrate,when inspected using an optical microscope. Put another way, “peeling”or a “peeling-related failure,” is defined as complete removal of thescratch resistant film(s) after undergoing the Garnet scratch test.Aspects of the disclosure exhibit substantially no peeling according tothis criterion when subjected to Garnet scratch testing with both 1 kgand 4 kg total applied load.

The crack mitigating composite 130 a-c (see FIGS. 1A-1C) may besubstantially optically transparent and free of light scattering, forexample, having an optical transmission haze of 10% or less, 9% or less,8% or less, 7% or less, 6% or less, 5% or less, 4% or less, 3% or less,2% or less, 1% or less and all ranges and sub-ranges therebetween. Thetransmission haze of the layer may be controlled by controlling theaverage sizes of pores within the crack mitigating composite 130 a-c, asdefined herein. Exemplary average pore sizes in the layer may include200 nm or less, 100 nm or less, 90 nm or less, 80 nm or less, 70 nm orless, 60 nm or less, 50 nm or less, 40 nm or less, 30 nm or less, 20 nmor less, 10 nm or less, 5 nm or less and all ranges and sub-rangestherebetween. These pore sizes can be estimated from light scatteringmeasurements, or directly analyzed using transmission electronmicroscopy (TEM) and other known methods.

In some embodiments, the crack mitigating composite 130 a-c may exhibita similar refractive index to either the glass-based substrate 120and/or hard film 110 to minimize optical interference effects.Accordingly, the crack mitigating composite 130 a-c can exhibit arefractive index that is somewhat above, equal to or somewhat below therefractive indices of the substrate 120 and/or the hard film 110.Additionally or alternatively, the crack mitigating composite 130 a-cmay exhibit a refractive index that is tuned to achieve anti-reflectiveinterference effects. The refractive index of the crack mitigatingcomposite 130 a-c can be engineered somewhat by controlling the relativeamounts and compositions of the inorganic and polymeric elements 33, 35along with the thicknesses of any layers serving as constituents of theelements 33, 35 (e.g., as consistent with the crack mitigatingcomposites 130 b, 130 c depicted in FIGS. 1B and 1C).

The thickness 13 a-c (which includes an average thickness where thethickness of the crack mitigating composite varies) of the crackmitigating composite 130 a-c employed in laminate articles 100 a-c maybe in the range of about 0.001 μm to about 10 μm (1 nm to 10,000 nm),from about 0.01 μm to about 1 μm (10 nm to about 1000 nm), from about0.05 μm to about 0.75 μm (50 nm to about 750 nm), from about 0.01 μm toabout 0.5 μm (10 nm to about 500 nm), from about 0.02 μm to about 0.2 μm(20 nm to about 200 nm). In one or more embodiments, the thickness 13a-c of the crack mitigating composite 130 a-c is in the range from about0.02 μm to about 10 μm, from about 0.03 μm to about 10 μm, from about0.04 μm to about 10 μm, from about 0.05 μm to about 10 μm, from about0.06 μm to about 10 μm, from about 0.07 μm to about 10 μm, from about0.08 μm to about 10 μm, from about 0.09 μm to about 10 μm, from about0.1 μm to about 10 μm, from about 0.01 μm to about 9 μm, from about 0.01μm to about 8 μm, from about 0.01 μm to about 7 μm, from about 0.01 μmto about 6 μm, from about 0.01 μm to about 5 μm, from about 0.01 μm toabout 4 μm, from about 0.01 μm to about 3 μm, from about 0.01 μm toabout 2 μm, from about 0.01 μm to about 1 micron, from about 0.02 μm toabout 1 micron, from about 0.03 to about 1 μm, from about 0.04 μm toabout 0.5 μm, from about 0.05 μm to about 0.25 μm or from about 0.05 μmto about 0.15 μm, and all ranges and sub-ranges between the foregoingvalues.

In one or more embodiments, thicknesses of the glass-based substrate120, hard film 110 and/or crack mitigating composite 130 a-c (e.g.,thicknesses 12, 11 and 13 a-c, respectively) may be specified inrelation to one another (see FIGS. 1A-1C). For example, the crackmitigating composite 130 a-c may have a thickness 13 a-c that is lessthan or equal to about 10 times the thickness 11 of the hard film 110.In another example, where a hard film 110 has a thickness 11 of about 85nm, the crack mitigating composite 130 a-c may have a thickness 13 a-cof about 850 nm or less. In yet another example, the thickness 13 a-c ofthe crack mitigating composite 130 a-c may be in the range from about 35nm to about 80 nm and the film 110 may have a thickness 11 in the rangefrom about 30 nm to about 300 nm. In a further example, the thickness 13a-c of the crack mitigating composite 130 a-c may be in the range fromabout 150 nm to about 450 nm and the thickness 11 of the hard film 110is in the range from about 1 micron to about 3 microns.

In one variant, the crack mitigating composite 130 a-c may have athickness 13 a-c that is less than or equal to about 9 times, 8 times, 7times, 6 times, 5 times, 4 times, 3 times or two times the thickness 11of the film 110, and all ranges and sub-ranges between the foregoingvalues. In another variant, the thickness 11 of the film 110 and thethickness 13 a-c of the crack mitigating composite 130 a-c are each lessthan about 10 μm, less than about 5 μm, less than about 2 μm, less thanabout 1 μm, less than about 0.5 μm, or less than about 0.2 μm, and allranges and sub-ranges between the foregoing values. The ratio of thecrack mitigating composite 130 a-c thicknesses 13 a-c to the film 110thickness 11 maybe, in some embodiments, in the range from about 1:1 toabout 1:20, in the range from about 1:2 to about 1:6, in the range fromabout 1:3 to about 1:5, or in the range from about 1:3 to about 1:4, andall ranges and sub-ranges between the foregoing values. In anothervariant, the thickness 13 a, 13 b of the crack mitigating composite 130a-c is less than about 0.4 μm and the thickness 11 of the film 110 isgreater than the crack mitigating composite 130 a-c.

Additionally or alternatively, the hard film 110 including one or moreof an indium-tin-oxide layer, a scratch-resistant layer (e.g.,AlO_(x)N_(y), AlN and combinations thereof), and an anti-reflectivelayer; and the crack mitigating composite 130 a-c form a stack element,wherein the stack element has an overall low optical reflectance. Forexample, the overall (or total) reflectance of such a stack element maybe 15% or less, 10% or less, 8% or less, 7% or less, 6.5% or less, 6% orless, 5.5% or less, and all ranges and sub-ranges between the foregoingvalues, across a visible wavelength range from 450-650 nm, 420-680 nm,or even 400-700 nm. The reflectance numbers above may be present in someembodiments including the reflectance from one bare (or uncoated) glassinterface (e.g., of the glass-based substrate 120), which isapproximately 4% reflectance from the uncoated glass interface alone, ormay be characterized as the reflectance for a first major surface of aglass-based substrate 120 and the stack element (and associatedinterfaces) disposed on the first major surface (excluding the 4%reflectance from an uncoated second major surface of the glass-basedsubstrate). The average reflectance from the stack element structure andthe stack element-glass coated interfaces alone (subtracting out thereflectance of the uncoated glass interface) may be less than about 5%,4%, 3%, 2%, or even less than about 1.5%, and all ranges and sub-rangesbetween the foregoing values, across a visible wavelength range from450-650 nm, 420-680 nm, or even 400-700 nm, in some cases when one ormore major surfaces of the glass-based substrate 120 is covered by atypical encapsulant (i.e., an additional film or layer) having anencapsulant refractive index of about 1.45-1.65. In addition, the stackelement may exhibit a high optical transmittance, which indicates bothlow reflectance and low absorptance, according to the generalrelationship: Transmittance=100%−Reflectance−Absorptance. The averagetransmittance values for the stack element (when neglecting reflectanceand absorptance associated with the glass-based substrate 120 orencapsulant layers alone) may be greater than about 75%, 80%, 85%, 90%,95%, or even 98%, and all ranges and sub-ranges between the foregoingvalues, across a visible wavelength range from 450-650 nm, 420-680 nm,or even 400-700 nm.

The optical properties of the laminate articles 100 a-c (see FIGS.1A-1C) may be adjusted by varying one or more of the properties of thehard film 110, crack mitigating composite 130 a-c and/or the glass-basedsubstrate 120. For example, the articles 100 a-c may exhibit a totalreflectance of 15% or less, 10% or less, 8% or less, 7% or less, 6.9% orless, 6.8% or less, 6.7% or less, 6.6% or less, 6.5% or less, 6.4% orless, 6.3% or less, 6.2% or less, 6.1% or less and/or 6% or less, andall ranges and sub-ranges between the foregoing values, over the visiblewavelength range from about 400 nm to about 700 nm. Ranges may furthervary as specified hereinabove, and ranges for the stack element (i.e.,as including the hard film 110 and the crack mitigating composite 130a-c)/coated glass interfaces alone are listed hereinabove. In morespecific embodiments, the articles 100 a-c described herein may exhibita lower average reflectance and greater average flexural strength thanarticles without a crack mitigating composite 130 a-c. In one or morealternative embodiments, at least two of optical properties, electricalproperties or mechanical properties of the article 100 a-c may beadjusted by varying the thickness(es) of the glass-based substrate 120,film 110 and/or the crack mitigating composite 130 a-c. Additionally oralternatively, the average flexural strength of the articles 100 a-c maybe adjusted or improved by modifying the thickness(es) of theglass-based substrate 120, film 110 and/or the crack mitigatingcomposite 130 a-c.

Additionally, glass-based substrates 120 coated with the crackmitigating composite 130 a-c may have a reflectance that is within 2% orwithin 1% of the glass-based substrate alone. The crack mitigatingcomposite may have a refractive index which is less than 1.55, from 1.35to 1.55, or no greater than 0.05 higher than the refractive index of thesubstrate. The crack mitigating composite may also have a combinedabsorptance and scattering level that is less than 5% of the incidentoptical energy across a visible wavelength range from 400-800 nm.

The articles 100 a-c (see FIGS. 1A-1C) may include one or moreadditional films (not shown) disposed on the glass-based substrate 120.In one or more embodiments of the article 100 a-c, the one or moreadditional films may be disposed on the hard film 110 or, as is moretypical, on the opposite major surface from the film 110. Certain of theadditional film(s) may be disposed in direct contact with the film 110.In one or more embodiments, the additional film(s) may be positionedbetween: 1) the glass-based substrate 120 and the crack mitigatingcomposite 130 a-c (e.g., in laminate articles 100 a-c); or 2) the crackmitigating composite 130 a-c and the film 110. In one or moreembodiments, both the crack mitigating composite 130 a-c and the film110 may be positioned between the glass-based substrate 120 and theadditional film(s). The additional film(s) may include a protectivelayer, an adhesive layer, a planarizing layer, an anti-splinteringlayer, an optical bonding layer, a display layer, a polarizing layer, alight-absorbing layer, reflection-modifying interference layers,scratch-resistant layers, barrier layers, passivation layers, hermeticlayers, diffusion-blocking layers and combinations thereof, and otherlayers known in the art to perform these or related functions. Examplesof suitable protective or barrier layers include layers containingSiO_(x), SiN_(y), SiO_(x)N_(y), other similar materials and combinationsthereof. Such layers can also be modified to match or complement theoptical properties of the hard film 110, the crack mitigating composite130 a-c and/or the glass-based substrate 120. For example, theprotective layer may be selected to have a similar refractive index asthe crack mitigating composite 130 a-c, the film 110, or the glass-basedsubstrate 120.

In one or more embodiments, the articles 100 a-c described may be usedin information display devices and/or touch-sensing devices. In one ormore alternative embodiments, the articles 100 a-c may be part of alaminate structure, for example, as a glass-polymer-glass laminatedsafety glass to be used in automotive or aircraft windows. An exemplarypolymer material used as an interlayer in these laminates is PVB(polyvinyl butyral), and there are many other interlayer materials knownin the art that can be used. In addition, there are various options forthe structure of the laminated glass, which are not particularlylimited. The articles 100 a-c may be curved or shaped in the finalapplication, for example as in an automotive windshield, sunroof, orside window. The thickness 10 a-c of the articles 100 a-c can vary, foreither design or mechanical reasons; for example, the articles 100 a-ccan be thicker at the edges than at the center of the article. Thearticles 100 a-c may be acid-polished or otherwise treated to remove orreduce the effect of surface flaws.

Some embodiments of the present disclosure pertain to cover glassapplications that utilize the articles 100 a-c described herein. In oneor more embodiments, the cover glass may include a laminated articlewith a glass-based substrate 120 (which may be strengthened or notstrengthened), a hard film 110 (e.g., AlO_(x)N_(y), AlN, SiO_(x)N_(y),SiAl_(v)O_(x)N_(y), Si₃N₄ and combinations thereof), and the crackmitigating composite 130 a-c comprising an inorganic element and apolymeric element. The laminated article 100 a-c may include one or moreadditional film(s) for reducing the reflection and/or providing aneasy-to-clean or anti-fingerprint surface on the laminated article. Inparticular, a ˜1-10 nm thick silane or fluorosilane layer may be appliedto the surface of the hard film to reduce friction, improvecleanability, or aid in scratch reduction at the user surface of thearticle.

Some embodiments of the present disclosure pertain to touch-sensingdevices including the articles described herein. In one or moreembodiments, the touch sensor device may include a glass-based substrate120 (which may be strengthened or not strengthened), a hard film 110(e.g., as comprising a transparent conductive oxide and ascratch-resistant material, e.g., AlO_(x)N_(y), AlN, SiO_(x)N_(y),SiAl_(v)O_(x)N_(y), Si₃N₄ and combinations thereof) and a crackmitigating composite 130 a-c. The transparent conductive oxide mayinclude indium-tin-oxide, aluminum-zinc-oxide, fluorinated tin oxide, orothers known in the art. In one or more embodiments, the conductiveoxide portion of the hard film 110 is discontinuously disposed on theglass-based substrate 120. In other words, conductive portions of thehard film 110 may be disposed on discrete regions of the glass-basedsubstrate 120 (with crack mitigating composite 130 a-c). The discreteregions with the film form patterned or coated regions (not shown),while the discrete regions without the film form unpatterned or uncoatedregions (not shown). In one or more embodiments, the patterned or coatedregions and unpatterned or uncoated regions are formed by disposing thefilm 110 continuously on a surface of the crack mitigating composite 130a-c, which in turn is on the surface of the glass-based substrate 120and then selectively etching away the film 110 in the discrete regionsso that there is no film 110 in those discrete regions. The film 110 maybe etched away using an etchant, for example, HCl or FeCl₃ in aqueoussolutions, for example, the commercially available TE-100 etchant fromTransene Co. In one or more embodiments, the crack mitigating composite130 a-c is not significantly degraded or removed by the etchant.Alternatively, the film 110 may be selectively deposited onto discreteregions of a surface of the crack mitigating composite 130 a-c, which,in turn, is on the surface of the glass-based substrate 120 to form thepatterned or coated regions and unpatterned or uncoated regions.

In one or more embodiments of the laminate articles 100 a-c having ahard film 110 that includes conductive oxide portions or discreteregions, the uncoated regions have a total reflectance that is similarto the total reflectance of the coated regions. In one or more specificembodiments, the unpatterned or uncoated regions have a totalreflectance that differs from the total reflectance of the patterned orcoated regions by about 5% or less, 4.5% or less, 4% or less, 3.5% orless, 3% or less, 2.5% or less, 2.0% or less, 1.5% or less or even 1% orless, and all ranges and sub-ranges between the foregoing values, acrossa visible wavelength in the range from about 400 nm to about 800 nm,from about 450 nm to about 650 nm, from about 420 nm to about 680 nm oreven from about 400 nm to about 700 nm.

In some embodiments of the present disclosure, articles 100 a-ccomprising a crack mitigating composite 130 a-c and a hard film 110,which may include indium-tin-oxide or other transparent conductiveoxides, exhibit resistivity that is acceptable for use of such articlesin touch sensing devices. In one or more embodiments, the films 110,when present in the articles disclosed herein, exhibit a sheetresistance of about 100 ohm/square or less, 80 ohm/square or less, 50ohm/square or less, or even 30 ohm/square or less. In such embodiments,the film may have a thickness of about 200 nm or less, 150 nm or less,100 nm or less, 80 nm or less, 50 nm or less or even 35 nm or less, andall ranges and sub-ranges between the foregoing values. In one or morespecific embodiments, such films, when present in the article 100 a-c,exhibit a resistivity of 10×10⁻⁴ ohm-cm or less, 8×10⁻⁴ ohm-cm or less,5×10⁻⁴ ohm-cm or less, or even 3×10⁻⁴ ohm-cm or less, and all ranges andsub-ranges between the foregoing values. Thus, the hard films 110, whenpresent in the articles 100 a-c disclosed herein with conductive oxideportions, can favorably maintain the electrical and optical performanceexpected of transparent conductive oxide films and other such films usedin touch sensor applications, including projected capacitive touchsensor devices.

The disclosure herein can also be applied to articles 100 a-c which arenot interactive or for display; for example, such articles may be usedin a case in which a device has a glass front side that is used fordisplay and can be interactive, and a back side that might be termed“decorative” in a very broad sense, meaning that backside can be“painted” in some color, have art work or information about themanufacturer, model and serial number, texturing or other features.

With regard to the optical properties of the laminate articles 100 a-c(see FIGS. 1A-1C), the hard film 110 can comprise a scratch-resistantmaterial, for example AlN, Si₃N₄, AlO_(x)N_(y), and SiO_(x)N_(y), whichpossesses a relatively high refractive index in the range from about 1.7to about 2.1. The glass-based substrates 120 employed in laminatearticles 100 a-c typically have refractive indices in the range fromabout 1.45 to about 1.65. Further, the crack mitigating composite 130a-c employed in articles 100 a-c typically has a refractive indexsomewhere near or between the refractive index ranges common to thesubstrate 120 and the film 110 (when present). The differences in theserefractive index values (e.g., between the substrate 120 and the crackmitigating composite 130 a-c) can contribute to undesirable opticalinterference effects. In particular, optical interference at theinterfaces 150 and/or 160 (see FIGS. 1A-1C) can lead to spectralreflectance oscillations that create apparent color observed in thearticles 100 a-c. The color shifts in reflection with viewing angle dueto a shift in the spectral reference oscillations with incidentillumination angle. Ultimately, the observed color and color shifts withincident illumination angle are often distracting or objectionable todevice users, particularly under illumination with sharp spectralfeatures, for example, fluorescent lighting and some LED lighting.Alternately or additionally, the crack mitigating composite 130 a-cand/or hard film 110 may have layers or sub-layers with alternating highand low refractive indices, thus providing an optical impedance tuningeffect which can be used to lower reflectance, control reflectance tomatch a target, lower color, or lower color shifts of the coatedarticle, as further illustrated in the Examples below.

According to aspects of this disclosure, observed color and color shiftsin the articles 100 a-c can be reduced by minimizing reflectance at oneor both of the interfaces 150 and 160 (see FIGS. 1A-1C), thus reducingreflectance oscillations and reflected color shifts for the entirearticle. In some aspects, the density, thickness, composition and/orporosity of the crack mitigating composite 130 a-c can be tailored tominimize such reflectance at the interfaces 150 and 160. For example,configuring the layer 130 a-c according to the foregoing aspects canreduce the amplitudes and/or oscillations of the reflectance across thevisible spectrum.

As used herein, the term “amplitude” includes the peak-to-valley changein reflectance or transmittance. As also used herein, the term“transmittance” is defined as the percentage of incident optical powerwithin a given wavelength range transmitted through the articles 100a-c. The term “average transmittance” refers to the spectral average ofthe light transmission multiplied by the luminous efficiency function,as described by CIE standard observer. The term “reflectance” issimilarly defined as the percentage of incident optical power within agiven wavelength range that is reflected from the articles 100 a-c. Ingeneral, transmittance and reflectance are measured using a specificline width. Furthermore, the phrase “average amplitude” includes thepeak-to-valley change in reflectance or transmittance averaged overevery possible 100 nm wavelength range within the optical wavelengthregime. As used herein, the “optical wavelength regime” includes therange from about 400 nm to about 800 nm.

According to one or more embodiments, the laminated articles 100 a-cexhibit an average transmittance of 85% or greater over the visiblespectrum. In some embodiments, the laminated articles 100 a-c canexhibit an average transmittance of 80% or greater, 82% or greater, 85%or greater, 90% or greater, 91% or greater, 92% or greater, 93% orgreater, 94% or greater, or 95% or greater, and all ranges andsub-ranges between the foregoing values.

In some aspects, the articles 100 a-c exhibit an average totalreflectance of 20% or less over the visible spectrum. Certainembodiments of the articles 100 a-c, for example, exhibit a totalreflectance of 20% or less, 15% or less, 10% or less, 9% or less, 8% orless, 7% or less, 6% or less, or 5% or less, 4% or less, 3% or less, 2%or less, and all ranges and sub-ranges between the foregoing values.

In accordance with one or more embodiments, the articles 100 a-c have atotal reflectivity that is the same or less than the total reflectivityof the glass-based substrate 120. In one or more embodiments, thearticles 100 a-c exhibit a relatively flat transmittance spectrum,reflectance spectrum or transmittance and reflectance spectrum over theoptical wavelength regime. In some embodiments, the relatively flattransmittance and/or reflectance spectrum includes an averageoscillation amplitude of about 5 percentage points or less along theentire optical wavelength regime, or wavelength range segments in theoptical wavelength regime. Wavelength range segments may be about 50 nm,about 100 nm, about 200 nm or about 300 nm, and all ranges andsub-ranges between the foregoing values. In some embodiments, theaverage oscillation amplitude may be about 4.5 percentage points orless, about 4 percentage points or less, about 3.5 percentage points orless, about 3 percentage points or less, about 2.5 percentage points orless, about 2 percentage points or less, about 1.75 percentage points orless, about 1.5 percentage points or less, about 1.25 percentage pointsor less, about 1 percentage point or less, about 0.75 percentage pointsor less, about 0.5 percentage points or less, about 0.25 percentagepoints or less, or about 0 percentage points, and all ranges andsub-ranges therebetween. In one or more specific embodiments, thearticles 100 and 100 a exhibit a transmittance over a selectedwavelength range segment of about 100 nm or 200 nm over the opticalwavelength regime, wherein the oscillations from the spectra have amaximum peak of about 80%, about 82%, about 84%, about 86%, about 87%,about 88%, about 89%, about 90%, about 91%, about 92%, about 93%, about94%, or about 95%, and all ranges and sub-ranges therebetween.

In some embodiments, the relatively flat average transmittance and/oraverage reflectance includes maximum oscillation amplitude, expressed asa percent of the average transmittance or average reflectance, along aspecified wavelength range segment in the optical wavelength regime. Theaverage transmittance or average reflectance of the laminated articles100 a-c would also be measured along the same specified wavelength rangesegment in the optical wavelength regime. The wavelength range segmentmay be about 50 nm, about 100 nm or about 200 nm. In one or moreembodiments, the articles 100 and 100 a exhibit an average transmittanceand/or average reflectance with an average oscillation amplitude ofabout 10% or less, about 5% or less, about 4.5% or less, about 4% orless, about 3.5% or less, about 3% or less, about 2.5% or less, about 2%or less, about 1.75% or less, about 1.5% or less, about 1.25% or less,about 1% or less, about 0.75% or less, about 0.5% or less, about 0.25%or less, or about 0.1% or less, and all ranges and sub-rangestherebetween. Such percent-based average oscillation amplitudes may beexhibited by the article along wavelength range segments of about 50 nm,about 100 nm, about 200 nm or about 300 nm, in the optical wavelengthregime. For example, an article according to this disclosure may exhibitan average transmittance of about 85% along the wavelength range fromabout 500 nm to about 600 nm, which is a wavelength range segment ofabout 100 nm, within the optical wavelength regime. The article may alsoexhibit a percent-based oscillation amplitude of about 3% along the samewavelength range (500 nm to about 600 nm), which means that along thewavelength range from 500 nm to 600 nm, the absolute (non-percent-based)oscillation amplitude is about 2.55 percentage points.

Some embodiments pertain to an electronic device incorporating thearticles 100 a-c disclosed herein (not shown). These electronic devicescan include any device or article with a display (e.g., consumerelectronics, including mobile phones, tablets, computers, wearables(e.g. watches), navigation systems, and the like), architecturalarticles, transportation articles (e.g., automotive, trains, aircraft,sea craft, etc.), appliance articles, or any article in which sometransparency, scratch-resistance, abrasion resistance or a combinationthereof is desired. A mobile phone can include a housing; electricalcomponents that are at least partially inside or entirely within thehousing and including at least a controller, a memory, and a display ator adjacent to the front surface of the housing; and a laminated article100 a-c at or over the front surface of the housing such that it is overthe display. Additional applications for the articles of the disclosuredo not necessarily include an electronic device, such as eyeglasses,sunglasses, windows, automotive or aircraft windshields, or glass-basedscreen protectors which are laminated to electronic devices using anadhesive.

In one or more embodiments, the method includes disposing the hard film110 and/or the crack mitigating composite 130 a-c via a vacuumdeposition process. In particular embodiments, such vacuum depositionprocesses may utilize temperatures of about 25° C., 50° C., 75° C., 100°C., 200° C., 300° C., 400° C., or more, and all ranges and sub-rangestherebetween. In some embodiments, the crack mitigating composite 130a-c may be formed by a wet process.

In one or more specific embodiments, the method includes controlling thethickness(es) of the crack mitigating composite 130 a-c and/or the hardfilm 110. Controlling the thickness(es) of the crack mitigatingcomposite 130 a-c and/or films (e.g., hard film 110) disclosed hereinmay be performed by controlling one or more processes for forming thecrack mitigating composite, stack and/or films so that the crackmitigating composite, stack and/or films are applied having a desired ordefined thickness. In some embodiments, the method includes controllingthe thickness(es) of the crack mitigating composite 130 a-c and/or thehard film 110 to maintain (or enhance, in some cases) the averageflexural strength of the glass-based substrate 120, the functionalproperties of the glass-based substrate 120 and/or the functionalproperties of the film 110.

In one or more alternative embodiments, the method includes controllingthe continuity of the crack mitigating composite 130 a-c and/or the hardfilm 110. Controlling the continuity of the crack mitigating composite130 a or stack 130 b may include forming a continuous crack mitigatingcomposite and removing a selected portion(s) of the crack mitigatingcomposite or stack to create a discontinuous crack mitigating composite.In other embodiments, controlling the continuity of the crack mitigatingcomposite or stack may include selectively forming the crack mitigatingcomposite or stack to form a discontinuous crack mitigating composite orstack. Such embodiments may use a mask, an etchant and combinationsthereof to control the continuity of the crack mitigating composite 130a-c.

In one or more embodiments, the method may include creating a controlledelastic modulus in the crack mitigating composite 130 a-c. The methodmay further include controlling the intrinsic film stresses of the crackmitigating composite 130 a, stack 130 b and/or the film 110 throughcontrol of deposition and fabrication processes of the crack mitigatingcomposite or stack.

The method may include disposing an additional film, as describedherein, on the glass-based substrate 120. In one or more embodiments,the method may include disposing the additional film on the glass-basedsubstrate such that the additional film is disposed between theglass-based substrate 120 and the crack mitigating composite 130 a-c,between the crack mitigating composite 130 a-c and the hard film 110 or,such that the film 110 is between the crack mitigating composite 130 a-cand the additional film. Alternatively, the method may include disposingthe additional film on the opposite major surface of the glass-basedsubstrate 120 from the surface on which the film is disposed.

In one or more embodiments, the method includes strengthening theglass-based substrate 120 before or after disposing the crack mitigatingcomposite 130 a-c, hard film 110 and/or an additional film on theglass-based substrate. The glass-based substrate 120 may be strengthenedchemically or otherwise. The glass-based substrate 120 may bestrengthened after disposing the crack mitigating composite 130 a-c onthe glass-based substrate 120 but before disposing the film 110 on theglass-based substrate. The glass-based substrate 120 may be strengthenedafter disposing the crack mitigating composite 130 a-c and the film 110on the glass-based substrate 120 but before disposing an additional film(if any) on the glass-based substrate. Where no additional film isutilized, the glass-based substrate 120 may be strengthened afterdisposing the crack mitigating composite 130 a-c and the film 110 on theglass-based substrate.

The following examples represent certain non-limiting embodiments of thedisclosure.

Example 1 Strength of Laminated Articles Having Five-LayerAl₂O₃/Polyimide Crack Mitigating Composites and Silicon Nitride HardFilms

Sample laminated articles designated Examples 1A-1C (“Exs. 1A, 1B, 1A1,1B1 and 1C”) were formed by providing Corning® 2320 Gorilla Glass®glass-based substrates according to the following composition: SiO₂ ofabout 67 mol %, B₂O₃ of about 4 mol %, Al₂O₃ of about 13 mol %, Na₂O ofabout 14 mol %, and MgO of about 2.5 mol %. The glass-based substrateshad a thickness of 1 mm (Exs. 1A, 1B) or 0.7 mm (Exs. 1A1, 1B1 and 1C).The glass-based substrates were strengthened by ion exchange to providea surface CS of about 800 MPa and a DOC of about 40 μm. The ion-exchangeprocess was carried out by immersing the glass-based substrate in amolten potassium nitrate (KNO₃) bath that was heated to a temperature inthe range from about 350° C. to 450° C. The glass-based substrates wereimmersed in the bath for a duration of 3-8 hours to achieve the surfaceCS and DOC. After completing the ion exchange process, the glass-basedsubstrates of Examples 1A-1C were cleaned in a 2% concentration KOHdetergent solution, supplied by Semiclean KG, having a temperature ofabout 50° C.

In Example 1, the Ex. 1C sample represents a control as it only containsa glass-based substrate. Similarly, the Exs. 1A and 1A1 samples alsoserve as a control because they possess a SiN_(x) hard film having athickness of about 440 nm and lack a crack mitigating composite. In theExs. 1A and 1A1 samples, the SiN_(x) hard film was deposited in aPlasma-Therm Versaline HDPCVD system at 200° C. with a silane precursorgas and nitrogen gas.

In Example 1, samples designated Exs. 1B and 1B1 were also prepared. Forthe Exs. 1B, 1B1 samples, strengthened glass-based substrates and hardfilms according to the Ex. 1A or 1A1 condition (e.g., a SiN_(x) filmhaving a thickness of about 440 nm and 0.7 mm or 1 mm thick glass-basedsubstrates) were prepared. In addition, Exs. 1B and 1B1 each possess acrack mitigating composite comprising a five-layer sequence of Al₂O₃ andpolyimide (“PI”) layers having the following thicknesses: 10 nm Al₂O₃(over the substrate)/75 nm PI/75 nm Al₂O₃/75 nm PI/75 nm Al₂O₃(immediately below the hard film).

Ring-on-ring (ROR) load to failure testing was used to demonstrate theretention of average flexural strength of Exs. 1A-1C, as shown in FIG.8. For ROR load-to-failure testing, the side with the film and/or crackmitigating composite was placed in tension. The ROR load-to-failuretesting parameters included a contact radius of 1.6 mm (0.063 inches), across-head speed of 1.2 mm/minute (0.047 inches/min), a load ringdiameter of 1.27 mm (0.5 inches), and a support ring diameter of 2.54 cm(1 inch). Before testing, an adhesive film was placed on both sides ofthe sample being tested to contain broken glass shards.

As illustrated in FIG. 8, the addition of a crack mitigating composite(as comprising a five-layer Al₂O₃/PI layer sequence) to a laminatearticle with a SiN_(x) hard film and a glass-based substrate (Exs. 1B (1mm thick substrate) and 1B1 (0.7 mm thick substrate)) resulted inlaminate articles with about a 36% and 42% increase (1 mm thick, and 0.7mm thick substrates) in failure load relative to similarly-configuredlaminate articles without such a crack mitigating composite (i.e., fromEx. 1A to 1B and from Ex. 1A1 to 1B1). As also shown by FIG. 8, theinclusion of a scratch-resistant film with a thickness of 440 nm (seeExs. 1B and 1B1) without any cracking mitigating composite significantlyreduces the average flexural strength of the glass-based substrate (seeEx. 1C). Given the relatively little difference in the increase in theaverage flexural strength observed between the two sets of sampleshaving differing glass-based substrate thicknesses (i.e., 36% and 42%,respectively), it is apparent that the thickness of the glass-basedsubstrate has little influence on the pronounced effect from the crackmitigating composite.

Example 2 Scratch Resistance of Laminated Articles Having Five-LayerAl₂O₃/Polyimide Crack Mitigating Composites and Silicon Nitride HardFilms

Referring now to FIGS. 9A-9D, optical microscopy images from laminatearticles comprising glass-based substrates having a hard film comprisinga 2 micron thick a silicon nitride layer and a fluorosilane layer, andno crack mitigating composite (FIG. 9A), a crack mitigating compositecomprising three thick alumina and two thin polyimide layers (FIG. 9B),a crack mitigating composite comprising three thin alumina and two thickpolyimide layers (FIG. 9C), or a crack mitigating layer comprisingpolyimide alone (FIG. 9D). Each of the samples depicted in FIGS. 9A-9Dwere subjected to a Garnet Scratch Test with a 4 kg load. Moreparticularly, the laminate articles depicted in FIG. 9A were configuredwith a fluorosilane and silicon nitride multi-layer hard film directlyover a glass-based substrate. The laminate articles depicted in FIGS. 9Band 9C were configured with a fluorosilane and silicon nitridemulti-layer hard film, followed by a five-layer crack mitigatingcomposite layer directly over a glass-based substrate. The five layercrack mitigating composite employed in the laminate articles of FIGS. 9Band 9C comprised: Al₂O₃/PI/Al₂O₃/PI/Al₂O₃ with thicknesses of:100/50/100/50/20 nm (FIG. 9B) and 25/125/25/125/20 nm (FIG. 9C) with the20 nm Al₂O₃ layer discovered to act as an adhesion promoting layer whenplaced adjacent to the glass substrate. In contrast, placing polyimidelayers or SiO₂ layers immediately adjacent to the glass substrate withsimilar crack mitigating composite structures was found to result inpoor adhesion and scratch resistance in such laminate articles. Finally,the laminate articles depicted in FIG. 9D were fabricated with afluorosilane and silicon nitride multi-layer hard film, and a polyimide(PI) layer with a 450 nm thickness disposed directly over a glass-basedsubstrate. In particular, the laminate articles of FIG. 9D served as acomparative example having a polymer-only (not a composite) crackmitigating layer. As is evident from the optical microscopy images ofFIGS. 9A-9D, the laminate articles with the five layer crack mitigatingcomposite structures (FIGS. 9B and 9C), consistent with aspects of thedisclosure, demonstrate comparable scratch resistance as the controlsample without a crack mitigating composite (FIG. 9A). In contrast, thelaminate articles with a monolayer-type crack mitigating layercomprising only polyimide (FIG. 9D) were prone to delamination duringthe Garnet Scratch Test.

Example 3 Optical Properties of Laminated Articles Having Seven-LayerAl₂O₃/Polyimide Crack Mitigating Composites and Silicon Nitride HardFilms

In FIG. 10, the transmittance spectra are provided for laminatedarticles designated without a crack mitigating composite and hard film(Ex. 2C, a glass-based substrate control) and three sets of samples withdiffering crack mitigating composites (Exs. 2A, 2B1 and 2B2). Moreparticularly, the laminate article designated Ex. 2A includes a crackmitigating composite over a glass-based substrate with the followingstructure and thicknesses: SiO₂ (over thesubstrate)/Al₂O₃/PI/Al₂O₃/PI/Al₂O₃/PI/Al₂O₃ and 80/10/50/10/80/10/50/20nm. Further, the laminate articles designated Exs. 2B1 and 2B2 includepolyimide layers derived form PMDA-ODA and ODPA-ODA, respectively,having thicknesses of 450 nm and 150 nm, respectively. As a hard filmdeployed over a crack mitigating composite would dominate the opticalproperties of the laminate articles of the disclosure, it is judged thatsamples without such hard films are representative for purposes ofdemonstrating the relative lack of any effect of the crack mitigatingcomposite on the overall optical properties of the laminate articles ofthe disclosure.

As shown in FIG. 10, the samples with the polyimide crack mitigatingcomposite layers (Exs. 2B1 and 2B2, traces 1002 and 1004, respectively)have relatively similar levels of optical transmission in the visiblewavelength range as compared to the baseline laminate article samplewithout a crack mitigating composite (Ex. 2C, trace 1006), indicatingthat PI layers have high optical transmissivity. While the laminatearticle sample with a seven-layer crack mitigating composite (Ex. 2A,trace 1000) exhibits somewhat more oscillations in transmittance in thevisible spectrum as compared to the other samples, it still demonstrateshigh optical transmissivity over the full visible spectrum. Withoutbeing bound by theory, it is also believed that the thicknesses andcompositions of the various layers within crack mitigating composite,comparable to the laminate article of Ex. 2A, can be designed toeliminate or otherwise minimize the optical interference effectsobserved in the results depicted in FIG. 10 for Ex. 2A. For example, alaminate article consistent with the principles of the disclosure with acrack mitigating composite with a more-optimized optical layer structureis detailed below in Example 6.

Example 4 Surface Roughness of Laminated Articles Having Al₂O₃/PolyimideCrack Mitigating Composites and Silicon Nitride Hard Films

Referring now to FIGS. 11A and 11B, atomic force microscopy (AFM) imagesare provided for laminate articles comprising a glass-based substrate, asilicon nitride hard film having a thickness of 440 nm and a crackmitigating composite comprising alumina and polyimide layers (FIG. 11A),according to some embodiments of the disclosure, and no crack mitigatingcomposite (FIG. 11B). In FIGS. 11A and 11B, the whiter regionscorrespond to peaks and other surface features indicative of the overallsurface roughness of these samples. Further, the root mean squared (RMS)roughness was measured on these samples using atomic force microscopy(AFM) techniques within a 2 micron×2 micron window on the outer surfaceof the respective silicon nitride films of these samples, as shown inFIGS. 11A and 11B. In particular, the sample depicted in FIG. 11A, witha crack mitigating composite and a silicon nitride hard film, had asurface roughness (over the silicon nitride film) of 1.68 nm. Incomparison, the sample depicted in FIG. 11B, with a silicon nitride hardfilm and no crack mitigating composite, had a surface roughness (overthe silicon nitride film) of 1.55 nm. Accordingly, the use of the crackmitigating composite only resulted in a nominal increase in surfaceroughness (i.e., from 1.55 nm to 1.68 nm), which is virtuallyindistinguishable when viewing the surface of the samples shown in FIGS.11A and 11B. As the exterior surface roughness of laminated articles forthe applications envisioned in the disclosure can contribute to scratchresistance, wear resistance and low friction performance, the laminatedarticles of the disclosure, with their crack mitigating composites andlayers, are particularly advantageous in that they offer other improvedproperties (i.e., strength retention) without significantly degradingthe exterior surface roughness of the article.

Example 5 Scratch Resistance of Laminated Articles Having Five-LayerAl₂O₃/Polyimide and BaF Crack Mitigating Composites and Silicon NitrideHard Films

Referring now to FIGS. 12A and 12B, optical microscopy images aredepicted from an article comprising a glass-based substrate, a siliconnitride hard film and a barium fluoride crack mitigating composite, assubjected to a Berkovich ramped scratch test (0 to 150 mN) (FIG. 12A);and from an article comprising a glass-based substrate, a siliconnitride hard film and a crack mitigating composite comprising aluminaand polyimide layers, as subjected to a Berkovich ramped scratch test(FIG. 12B). In FIGS. 12A and 12B, the scratched surfaces of the samplesare shown and the scratch test was conducted from left to right, withincreasing load levels as the stylus was moved from left to right overthe sample. The load levels are increased in a linear fashion as afunction of distance moved over the sample. Accordingly, the distancetraveled by the stylus up to the point of a delamination can be used tomeasure the load level associated with the delamination.

As is evident from the results of the Berkovich ramped test on thelaminate article depicted in FIG. 12A, which includes a crack mitigatingcomposite of barium fluoride with a thickness of 300 nm and a siliconnitride hard film having a thickness of 2 μm, a delamination wasobserved at about 100 mN during the test. That is, the wear trackobserved in the samples shown in FIG. 12A is a scratch with a narrowwidth that substantially widens upon the delamination in the last thirdof the wear track at the right-hand side of the sample. In contrast, thelaminate article depicted in FIG. 12B, which includes a crack mitigatingcomposite with a five-layer structure of Al₂O₃/PI/Al₂O₃/PI/Al₂O₃ havingthicknesses of 20 nm/50 nm/100 nm/50 nm/100 nm and a silicon nitridehard film having a thickness of 2 μm did not experience any delaminationup to a scratch load of 150 mN. That is, the stylus was moved over thesample shown in FIG. 12B from left to right with an increasing load upto 150 mN and no evidence of any delamination was observed.

Example 6 Optical Properties of a Laminate Article Having a Five-LayerAl₂O₃/Polyimide Crack Mitigating Composite and a SiO₂/AlO_(x)N_(y)Scratch-Resistant Film

As detailed below in Table 1, a laminated article was prepared with acrack mitigating composite and hard film structure, as configured tooptimize optical properties, according to an embodiment of thedisclosure. In particular, a crack mitigating composite that comprisesalternating polyimide and Al₂O₃ layers was formed over a primary surfaceof a glass substrate. As also demonstrated below in Table 1, ascratch-resistant film that comprises alternating SiO₂ and AlO_(x)N_(y)layers was formed over the crack mitigating composite. The individuallayer materials were fabricated by thermal and e-beam evaporation forthe polyimide and Al₂O₃ layers, respectively, and reactive sputteringfor the SiO₂ and AlO_(x)N_(y) layers. Further, the AlO_(x)N_(y) layerswere fabricated such that each such layer comprises about 10 mol %oxygen.

The individual layer optical properties of the laminated articles werecharacterized by spectroscopic ellipsometry and then placed into a thinfilm optical model to develop the structure listed below in Table 1.That is, optical modeling was conducted to optimize the layerthicknesses to demonstrate optimized optical performance of a laminatearticle comprising a five-layer crack mitigating composite. As listedbelow in Table 1, the refractive index values for each of the layersassociated with crack mitigating composite and the scratch-resistantfilm are reported from optical measurements at a reference wavelength of550 nm.

TABLE 1 Layer Material Refractive Index Thickness (nm) N/A Air 1 N/A 1SiO₂ 1.4685 102.9 2 AlO_(x)N_(y) 1.9540 32.7 3 SiO₂ 1.4685 14.6 4AlO_(x)N_(y) 1.9540 2000 5 SiO₂ 1.4685 8.1 6 AlO_(x)N_(y) 1.9540 39.2 7SiO₂ 1.4685 16.7 8 AlO_(x)N_(y) 1.9540 14.0 9 Al₂O₃ 1.6629 6.53 10PMDA-ODA polyimide 1.6862 41.3 11 Al₂O₃ 1.6629 67.3 12 PMDA-ODApolyimide 1.6862 114.0 13 Al₂O₃ 1.6629 24.8 Substrate Glass 1.5063

Referring now to FIGS. 13A and 13B, two-surface transmittance (i.e., asincluding both sides of the coated laminated article) and first-surfacereflectance (i.e., as considering only the coated side of the laminatedarticle) modeled data are presented, as obtained from a laminate articlethat is configured as listed in Table 1. The two-surface transmittancewas for a 1-mm substrate under the assumption that the adsorption in theglass could be safely ignored. Accordingly, the results would not bedifferent for 0.7 mm thickness (or other thickness) under the sameassumption and, therefore, no particular thickness is shown in Table 1.As shown in FIG. 13A, the transmittance at angle of incidence (AOI) of6, 20 and 40 degrees is above 90% in the wavelength range of 420 to 700nm. Further, the transmittance at angle of incidence (AOI) of 60 degreesis above 84% within the same wavelength range. As shown in FIG. 13B, thereflectance at AOI of 6, 20 and 40 degrees is below 5% within the samewavelength range of 420 to 700 nm. Further, the reflectance at AOI of 60degrees is below 10% for the same wavelength range.

Referring now to FIGS. 14A and 14B, two-surface transmitted color andfirst-surface reflected color modeled data are presented, as obtainedfrom a laminate article that is configured as listed in Table 1. Thecolor data shown in FIGS. 14A and 14B are such that positive values arered and negative values are green for a*, and positive values are yellowand negative values are blue for b*. More particularly, the estimatedmeasurements shown in FIGS. 14A and 14B are made for all angles ofincidence between 0 and 90 degrees with D65 and F2 standard illuminants,as understood by those with ordinary skill in the field of thedisclosure. With regard to FIG. 14A, the transmitted color is between 0and −1 in the a* coordinate and between 0 and +4 in the b* coordinate,for all angles of incidence. With regard to FIG. 14B, the reflectedcolor is between −2 and +2 in the a* coordinate and between −5 and +2for the b* coordinate, for all angles of incidence.

Referring now to FIG. 15, first-surface photopic reflectance modeledoptical data are presented, as obtained from a laminate article that isconfigured as listed in Table 1. The estimated measurements shown inFIG. 15 are made for all angles of incidence between 0 and 90 degreesboth D65 and F2 standard illuminants. From FIG. 15, it is evident thatthe reflectance is less than 2% for angles of incidence between 0 and 40degrees, and the reflectance is less than 6% for angles of incidencebetween 0 and 60 degrees.

While the disclosure has been described with respect to a limited numberof embodiments for the purpose of illustration, those skilled in theart, having benefit of this disclosure, will appreciate that otherembodiments can be devised which do not depart from the scope of thedisclosure as disclosed herein. Accordingly, various modifications,adaptations and alternatives may occur to one skilled in the art withoutdeparting from the spirit and scope of the present disclosure.

We claim:
 1. An article, comprising: a glass-based substrate comprisinga first major surface opposing a second major surface; a crackmitigating composite over the first major surface, the compositecomprising at least one inorganic element and a polymeric element; afirst film layer disposed on the crack mitigating composite, the filmcomprising an elastic modulus greater than or equal to the elasticmodulus of the glass-based substrate; and a second film layer disposedon the second major surface, wherein the second film layer comprises amulti-layer anti-reflection coating, and the first film layer comprisesat least one of a metal-containing oxide, a metal-containing oxynitride,a metal-containing nitride, a metal-containing carbide, asilicon-containing polymer, a carbon, a semiconductor, and combinationsthereof, and wherein the at least one inorganic element of the crackmitigating composite comprises two or more inorganic layers and thepolymeric element corresponds to a polymeric layer, wherein one of thetwo or more inorganic layers is in contact with the substrate andanother of the two or more inorganic layers is in contact with the firstfilm layer.
 2. The article of claim 1, wherein the article ischaracterized by an average flexural strength that is greater than orequal to about 50% of an average flexural strength of the substrate, asmeasured by ROR testing using an average from five (5) or more samples.3. The article of claim 1, wherein the first film layer is furthercharacterized by an indentation hardness of greater than or equal toabout 8 GPa.
 4. The article of claim 1, wherein the inorganic elementcomprises an oxide, a nitride or an oxynitride, and the polymericelement comprises at least one of a polyimide, a polycarbonate, apolyurethane, a polyester, and a fluorinated polymer.
 5. The article ofclaim 1, wherein the article is further characterized by a lighttransmissivity of greater than or equal to 50% in the visible spectrumfrom about 400 nm to about 800 nm.
 6. The article of claim 1, whereinthe article is further characterized by a pencil hardness of 9H orgreater.
 7. The article of claim 1, wherein the article is furthercharacterized by a delamination threshold of 150 mN or more, as testedusing a Berkovich Ramped Scratch Test on the first film layer.
 8. Thearticle of claim 1, wherein the first film layer comprises a multi-layerantireflection coating, and further wherein the crack mitigatingcomposite and the first film layer collectively comprise a photopicaverage single-side reflectance of less than about 2%.
 9. The article ofclaim 1, wherein the crack mitigating composite is characterized by anelastic modulus of greater than 30 GPa.
 10. The article according toclaim 1, wherein the inorganic element comprises three inorganic layerswith two organic layers of the organic element disposed therebetween.11. The article according to claim 10, wherein the inorganic elementcomprises Al₂O₃ and the polymeric element comprising a polyimide.
 12. Anarticle, comprising: a glass-based substrate comprising a first majorsurface opposing a second major surface; a crack mitigating compositeover the first major surface, the composite comprising at least oneinorganic element and a polymeric element, wherein the crack mitigatingcomposite is characterized by an elastic modulus ratio between theinorganic element and the polymeric element of greater than 10:1; afirst film layer disposed on the crack mitigating composite, the filmcomprising an elastic modulus greater than or equal to the elasticmodulus of the glass-based substrate; and a second film layer disposedon the second major surface, wherein the second film layer comprises amulti-layer anti-reflection coating, and the first film layer comprisesat least one of a metal-containing oxide, a metal-containing oxynitride,a metal-containing nitride, a metal-containing carbide, asilicon-containing polymer, a carbon, a semiconductor, and combinationsthereof, and wherein the at least one inorganic element of the crackmitigating composite comprises two or more inorganic layers and thepolymeric element corresponds to a polymeric layer, wherein one of thetwo or more inorganic layers is in contact with the substrate andanother of the two or more inorganic layers is in contact with the firstfilm layer.
 13. The article of claim 12, wherein the article ischaracterized by an average flexural strength that is greater than orequal to about 50% of an average flexural strength of the substrate, asmeasured by ROR testing using an average from five (5) or more samples.14. The article of claim 12, wherein: the inorganic element comprises anoxide, a nitride or an oxynitride, and the polymeric element comprisesat least one of a polyimide, a polycarbonate, a polyurethane, apolyester, and a fluorinated polymer; the article is furthercharacterized by a light transmissivity of greater than or equal toabout 50% in the visible spectrum from about 400 nm to about 800 nm; andthe article is further characterized by a pencil hardness of 9H orgreater.
 15. An article, comprising: a glass-based substrate comprisinga first major surface and a second major surface opposing the firstmajor surface; a crack mitigating composite over the first majorsurface, the crack mitigating composite comprising at least oneinorganic element and a polymeric element; a first film layer disposedon the crack mitigating composite; and a second film layer disposed onthe second major surface, wherein the at least one inorganic element ofthe crack mitigating composite comprises two or more inorganic layersand the polymeric element corresponds to a polymeric layer, wherein oneof the two or more inorganic layers is in contact with the substrate andanother of the two or more inorganic layers is in contact with the firstfilm layer.
 16. The article of claim 15, wherein the second film layercomprises a multi-layer anti-reflection coating.
 17. The article ofclaim 15, wherein the first film layer comprises at least one of ametal-containing oxide, a metal-containing oxynitride, ametal-containing nitride, a metal-containing carbide, asilicon-containing polymer, a carbon, a semiconductor, and combinationsthereof.
 18. The article of claim 15, wherein the crack mitigatingcomposite is characterized by an elastic modulus ratio between theinorganic element and the polymeric element of greater than 10:1. 19.The article of claim 15, wherein the at least one inorganic elementcomprises an oxide, a nitride or an oxynitride, and the polymericelement comprises at least one of a polyimide, a polycarbonate, apolyurethane, a polyester, and a fluorinated polymer.
 20. The article ofclaim 15, wherein the inorganic element comprises three inorganic layersand the organic element comprises two organic layers disposed betweenthe inorganic layers.
 21. The article of claim 20, wherein the inorganicelement comprises Al₂O₃ and the polymeric element comprising apolyimide.